Increase in paratyphoid fever cases in Japanese travellers returning from Cambodia in 2013.

In 2013, an unusual increase of paratyphoid fever cases in travellers returning from Cambodia was reported in Japan. From December 2012 to September 2013, 18 cases of Salmonella Paratyphi A infection were identified. Microbiological analyses revealed that most isolates had the same clonal identity, although the epidemiological link between these cases remains unclear. It was inferred that the outbreak was caused by a common and persistent source in Cambodia that was likely to have continued during 2014. The information of surveillance and laboratory data from cases arising in travellers from countries with limited surveillance systems should be timely shared with the country of origin.

Vibrio cholerae O1 El Tor from southern Vietnam in 2010 was molecularly distinct from that present from 1999 to 2004.

The Vibrio cholerae O1 (VCO1) El Tor biotype appeared during the seventh cholera pandemic starting in 1961, and new variants of this biotype have been identified since the early 1990s. This pandemic has affected Vietnam, and a large outbreak was reported in southern Vietnam in 2010. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem-repeat analyses (MLVA) were used to screen 34 VCO1 isolates from the southern Vietnam 2010 outbreak (23 patients, five contact persons, and six environmental isolates) to determine if it was genetically distinct from 18 isolates from outbreaks in southern Vietnam from 1999 to 2004, and two isolates from northern Vietnam (2008). Twenty-seven MLVA types and seven PFGE patterns were identified. Both analyses showed that the 2008 and 2010 isolates were distinctly clustered and separated from the 1999-2004 isolates.

Salmonella enterica serotype Paratyphi A carrying CTX-M-15 type extended-spectrum beta-lactamase isolated from a Japanese traveller returning from India, Japan, July 2013.

Emerging drug resistance in Salmonella Typhi and S. Paratyphi is a substantial public health concern. We report what appears to be the first case and isolation of multidrug resistant S. Paratyphi A carrying CTXM-15-type extended-spectrum beta-lactamase from a Japanese traveller returning from India.

Salmonella enterica serovar Typhi in Japan, 2001-2006: emergence of high-level fluoroquinolone-resistant strains.

The phage types and antimicrobial susceptibilities of 226 isolates of Salmonella enterica serovar Typhi from imported cases in Japan between 2001 and 2006 were investigated. Most (93.8%) had travelled to Asian countries, particularly South East Asia. Twenty-one phage types were identified with E1 (30.5%), UVS (15.9%) and B1 (9.3%) being the most common. The frequency of multidrug-resistant strains reached 37.0% in 2006 with phage types E1 and E9 predominating. Almost half (48.2%) of the isolates were resistant to nalidixic acid and two isolates displayed high-level fluoroquinolone resistance. Three mutations, two in gyrA and one in parC, were identified in both isolates.

The worldwide spread of ciprofloxacin-resistant Shigella sonnei among HIV-infected men who have sex with men, Taiwan.

Ciprofloxacin-resistant shigellosis outbreaks among men who have sex with men (MSM) have not been reported in Asia. During 3 March to 6 May 2015, the Notifiable Disease Surveillance System detected nine non-imported Shigella sonnei infections among human immunodeficiency virus (HIV) -infected Taiwanese MSM. We conducted a molecular epidemiological investigation using a 1 : 5 matched case-control study and laboratory characterizations for the isolates. Of the nine patients, four reported engagement in oral-anal sex before illness onset. Shigellosis was associated with a syphilis report within 12 months (adjusted odds ratio (aOR) 8.6; 95% CI 1.05-70.3) and no HIV outpatient follow-up within 12 months (aOR 22.3; 95% CI 2.5-201). Shigella sonnei isolates from the nine patients were all ciprofloxacin-resistant and the resistance was associated with S83L and D87G mutations in gyrA and S80I mutation in parC. The nine outbreak isolates were discriminated into two closely related pulsed-field gel electrophoresis (PFGE) genotypes and seven 8-locus multilocus variable-number tandem repeat analysis (MLVA8) types that suggest multiple sources of infections for the outbreak and possible under-recognition of infection among Taiwanese MSM. The outbreak isolates were characterized to be variants of the intercontinentally transmitted SS18.1 clone, which falls into the globally prevalent phylogenetic sub-lineage IIIb. Inter-database pattern similarity searching indicated that the two PFGE genotypes had emerged in the USA and Japan. The epidemiological characteristics of this outbreak suggest roles of risky sexual behaviours or networks in S. sonnei transmission. We urge enhanced surveillance and risk-reduction interventions regionally against the interplay of HIV and shigellosis among MSM.

Inducible stx2 phages are lysogenized in the enteroaggregative and other phenotypic Escherichia coli O86:HNM isolated from patients.

We characterized two Shiga toxin-producing Escherichia coli (STEC) O86:HNM isolates from a patient with hemolytic uremic syndrome (HUS) or bloody diarrhea. Both of them did not possess the eaeA gene. However, the isolate from a HUS patient carried genetic markers of enteroaggregative E. coli (EAEC) and showed aggregative adherence pattern to HEp-2 cells. The other isolate from bloody diarrhea, which was negative with EAEC markers, was diffusely adhered to HEp-2 cells. The stx2 gene in both E. coli O86:HNM strains was encoded in each infectious phage, which was partially homologous to that of strain EDL933, a STEC O157:H7. These results will help to explain the genotypic divergences of STEC.

Salmonella typhimurium DT104 from livestock in Japan.

We examined the distribution of multidrug-resistant Salmonella enterica serotype Typhimurium definitive phage type 104 (DT104) among Japanese livestock from 1973 to 1998. The 144 S. Typhimurium field isolates were tested for susceptibility to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline, kanamycin, trimethoprim, nalidixic acid, and norfloxacin. Thirty-six of 68 strains which exhibited resistance to five or more antimicrobials (ACSSuT+) were identified as DT104. Results of plasmid profiling showed that all DT104 strains retain a 90-kb virulence plasmid, while 20 of 36 strains possessed a few additional small plasmids ranging from 2 to 4 kb. These results showed that DT104 strains have existed in Japanese livestock since 1990, and that this phage type may be an important pathogen for cattle in Japan.

Molecular analysis of Salmonella Enteritidis isolates resistance to ampicillin and streptomycin from three outbreaks of food poisoning in Shiga prefecture.

In 1998 and 1999, there were three outbreaks caused by Salmonella Enteritidis in Shiga Prefecture. One outbreak was suspected to be a diffuse outbreak, caused by frozen cream puffs that had been sold in chain stores throughout Shiga Prefecture between the beginning of September and the beginning of October, 1998. The other outbreaks occurred in May and in August, 1999. All isolates of the three outbreaks showed an identical lysis pattern against the typing phage, though this pattern did not conform to the current scheme, so-called RDNC. In addition all isolates were resistant to ampicillin and streptomycin. However, the patterns of pulsed-field gel electrophoresis strongly indicated that the three outbreaks were actually independent.

[Multidrug-resistant and fluoroquinolone-resistant Salmonella enterica serotype Typhimurium definitive phage type 12 isolated from infantile diarrhea].

A 35-day-old male infant was admitted to our hospital, presenting a high fever, vomiting, and diarrhea. Multidrug-resistant and fluoroquinolon-resistant Salmonella serotype Typhimurium was isolated from his stool. The phage type of the strain was DT12. The strain was resistant to ampicillin, streptomycin, gentamicin, tetracycline, chloramphenicol, sulfamethoxazole-trimethoprim, and fluoroquinolones (levofloxacin; MIC 8 micrograms/ml, norfloxacin; 24 micrograms/ml, ciprofloxacin; 16 micrograms/ml, sparfloxacin; 32 micrograms/ml). He was cured by antibiotic therapy using fosfomycin (< or = 1 microgram/ml). We could not determine a route of infection. Domestic surveillance for fluoroquinolon-resistant Sallmonella is necessary.

[Isolation of Shiga toxin-producing Escherichia coli O157:H7 from processed salmon roe associated with the outbreaks in Japan, 1998, and a molecular typing of the isolates by pulsed-field gel electrophoresis].

Shiga toxin-producing Escherichia coil (STEC) O157 were isolated from processed salmon roe which had been a suspected food item in sporadic infections which occurred in Japan in 1998. A total of 45 samples of the processed salmon roe were pre-enriched in trypticase soy broth (TSB) at 36 degrees C for 6 h and novobiocin-supplemented modified EC broth (mEC-NB) at 42 degrees C for 18 h. After the pre-enrichments, the cultures were examined for possible occurrence of STEC O157, using an immunomagnetic separation (IMS) method. From the examination, a total of 84 strains of STEC O157:H7 that were positive for both stx 1 and stx 2 genes were isolated. By applying the most-probable-number technique, it was estimated that the number of STEC O157 was in the range of 0.73-1.5 per 10 g of the processed salmon roe. Subsequent analysis of the isolates by a pulsed-field gel electrophoresis (PFGE) revealed a pattern commonly seen in 82 isolates and another pattern in two isolates. Clinical isolates from 7 patients also showed an identical pattern to those of the 82 isolates and one isolate from a patient showed the other pattern identical to those of the two isolates. The isolates were found to belong to the phage type 14.

[Drug-resistance and definitive type 104 of Salmonella serovar typhimurium isolated from sporadic cases in Tokyo, 1980-1998].

A total of 674 Salmonella serovar Typhimurium (S. Typhimurium) strains consisting of 522 domestic strains and 152 imported strains isolated in Tokyo, 1980-1998, were examined regarding their drug-resistance and phage-type. Domestic strains accounted for 6.2% of all Salmonella (8,359 strains) isolated from domestic cases, and imported strains accounted for 3.7% of all Salmonella (4,083 strains) isolated from imported cases. A drug-resistance test using 9 drugs (CP, TC, SM, KM, ABPC, ST, NA, FOM, and NFLX) showed that 245 strains (46.9%) of the domestic strains and 109 strains (71.7%) of the imported strains were resistant to some of the drugs, excluding FOM and NFLX. Drugs with a high resistance rate were TC, SM, ABPC, and CP for both groups. Drug-resistance patterns of the resistant strains varied among the 40 types. Among those, prevalent patterns recognized were CP.TC.SM.ABPC, CP.TC.SM.KM.ABPC, TC.SM, SM, and TC.KM in the domestic strains, and TC, CP.TC.SM.ABPC, CP.TC.SM.KM.ABPC, CP.TC.SM.KM.ABPC.ST and TC.KM in the imported strains. The results of the phage-typing test revealed that 31 strains of 52 domestic strains tested, and 13 strains of 46 imported strains tested were definitive type 104 (DT104). Those resistance patterns were CP.TC.SM.ABPC.SU (43 strains) and CP.TC.SM.KM.ABPC.SU (1 strain).

[Genes involved in the virulence of enterohemorrhagic Escherichia coli].

Some of the virulent genes of enterohemorrhagic E. coli(EHEC) are described. stx, bfpA, eaeA and ehxA encode an enterocytotoxin homologous to Shiga toxin, bundle-forming pilus, intimin and an RTX toxin, respectively. In pathogenesis, although bfp and eae cause diarrhea, and ehx and stx seem to cause hemorrhagic colitis and hemolytic uremic syndrome, many problems remain for prevention and treatment of these symptoms. In evolution, it is intriguining that the virulent genes of EHEC might be mediated by phages, plasmids and so on, because stx is derived from a bacterio-phage, bfpA is located in a plasmid in enteropathogenic E. coli(EPEC) though it has not yet been cloned in EHEC, eaeA is one of the genes in LEE(locus of enterocyte effacement), a putative genetic cassette ubiquitous for EPEC and EHEC, and ehxA is in a plasmid.

Operation status of the electron cyclotron resonance ion source at Gunma University.

An ECR ion source of Gunma University Heavy Ion Medical Center, so-called KeiGM [M. Muramatsu, A. Kitagawa, Y. Sakamoto, S. Sato, Y. Sato, H. Ogawa, S. Yamada, H. Ogawa, Y. Yoshida, and A. G. Drentje, Rev. Sci. Instrum. 76, 113304 (2005)], has been operated for cancer therapy and physical/biological experiment since 2010. KeiGM produces typically 230 µA of 10 keV/u C(4+) ions from CH4 gases. The vacuum pressure is kept between 1.2 × 10(-4) and 1.7 × 10(-4) Pa so as to suppress the pulse-to-pulse current fluctuation within ±10%. The extraction electrode is cleaned every 6-8 months in order to remove deposited carbon, which increases the leak current and discharge. In order to investigate the possibility of long-term operation without such maintenances, oxygen aging for the cleaning of the extraction electrode has been tested in the test bench. The same-designed ion sources at National Institute of Radiological Sciences and SAGA Heavy Ion Medical Accelerator in Tosu (SAGA-HIMAT) are also operated with stable C(4+) current, which are suitable for the continuous operation for cancer therapy.

Distinguishable epidemics of multidrug-resistant Salmonella Typhimurium DT104 in different hosts.

The global epidemic of multidrug-resistant Salmonella Typhimurium DT104 provides an important example, both in terms of the agent and its resistance, of a widely disseminated zoonotic pathogen. Here, with an unprecedented national collection of isolates collected contemporaneously from humans and animals and including a sample of internationally derived isolates, we have used whole-genome sequencing to dissect the phylogenetic associations of the bacterium and its antimicrobial resistance genes through the course of an epidemic. Contrary to current tenets supporting a single homogeneous epidemic, we demonstrate that the bacterium and its resistance genes were largely maintained within animal and human populations separately and that there was limited transmission, in either direction. We also show considerable variation in the resistance profiles, in contrast to the largely stable bacterial core genome, which emphasizes the critical importance of integrated genotypic data sets in understanding the ecology of bacterial zoonoses and antimicrobial resistance.

Cloning and functional analysis of the ndk1 gene encoding nucleoside-diphosphate kinase in Schizosaccharomyces pombe.

We cloned the ndk1 gene encoding a subunit of nucleoside-diphosphate kinase (NDK) from Schizosaccharomyces pombe, by using polymerase chain reaction. The deduced ndk1 gene product has 151 amino acid residues and is approximately 60% identical with both Saccharomyces cerevisiae and mammalian NDKs. The gene product exhibited NDK activity and cross-reacted with antibodies raised against rat NDK. Disruption of ndk1 greatly reduced the cellular NDK activity but caused no obvious phenotype in cell growth and sexual development of the organism. However, a mutated allele of ndk1 could inhibit sexual development in a dominant-negative manner. This allele carried a point mutation in cysteine 116, which locates next to the putative active center histidine 117, and the mutant gene product showed no NDK activity. Gene expression inducible in response to mating pheromone signaling was decreased in cells carrying the dominant-negative allele. Cases have been reported in higher eukaryotes in which NDK appears to play a more sophisticated role than a simple catalyst in cell physiology, and the results of this study suggest that S. pombe NDK may also perform such a role in regulation of sexual development in the fission yeast.