Differences between Orofacial Inflammation and Cancer Pain

Rat models of orofacial cancer exhibit both allodynia and hyperalgesia; however, it is unclear whether cancer-induced pain is secondary to cancer-induced inflammation. To address this question, we compared the effects of an anti-inflammatory drug, indomethacin, on pain and neurochemical changes in the medullary dorsal horn in orofacial inflammation and cancer models. Daily peripheral administration of indomethacin largely suppressed mechanical allodynia and thermal hyperalgesia in the inflammation model. The same procedure suppressed allodynia and hyperalgesia in the cancer model, but the suppression was weak when compared with that in the inflammation model. In the medullary dorsal horn, calcitonin gene-related peptide and substance P levels were significantly increased in the inflammation model, but did not change in the cancer model. These results suggest that pain in the orofacial cancer model is not significantly mediated by cancer-induced peripheral inflammation, although it may have some involvement.

Lysine decarboxylase of Vibrio parahaemolyticus: kinetics of transcription and role in acid resistance

AIM

The aim of this study was to investigate the detailed mechanisms of acid resistance in Vibrio parahaemolyticus.

METHODS AND RESULTS

All 11 strains of V. parahaemolyticus survived lethal acidic conditions following acid adaptation, and accumulation of cadaverine was detected. The addition of lysine improved survival, suggesting that lysine decarboxylase plays a role in the adaptive acid tolerance response. Two open reading frames (ORF) in V. parahaemolyticus, which are separated by a noncoding region, were found to be highly homologous to bacterial lysine decarboxylase (cadA) and lysine/cadaverine antiporter (cadB) genes. Transcriptional analyses of this operon revealed acid induction and enhanced induction by external lysine. The relative expression ratio of each transcript was found to follow the trend of cadA mRNA > cadB mRNA > cadBA bi-cistronic mRNA. A mutated strain, with a disrupted cadA gene, showed attenuated acid survival.

CONCLUSIONS

We identified the lysine decarboxylase gene operon of V. parahaemolyticus. Expression of this operon was induced under acidic conditions. The cadA-mutated strain constructed in this study showed weaker tolerance to acidic conditions than the wild-type strain.

SIGNIFICANCE AND IMPACT OF THE STUDY

Vibrio parahaemolyticus utilizes the lysine decarboxylation pathway for survival in acidic conditions.

Galanin inhibits neural activity in the subfornical organ in rat slice preparation

The activation of the subfornical organ (SFO), a circumventricular organ, induces water intake and vasopressin release. Since central administrations of galanin (GAL) suppress water intake and vasopressin release, GAL may inhibit the neural activity of SFO neurons. In the present study, we investigated effects of GAL on the SFO using molecular biological, electrophysiological and anatomical techniques. Reverse transcription-polymerase chain reaction analysis demonstrated the presence in the SFO of rats of the mRNAs for each of the three known GAL receptor subtypes (GalR1, GalR2 and GalR3). In extracellular recordings in SFO slice preparations, GAL dose-dependently inhibited the neural activity of cells from a number of recording sites. Many GAL-sensitive SFO neurons showed excitatory responses to angiotensin II (ANGII). The GalR1 agonist M617 inhibited the activity of SFO neurons, whereas the GalR2 and GalR3 agonist GAL(2-11) had almost no effect. In patch-clamp recordings, GAL induced an outward current in SFO neurons without influencing synaptic currents. An immunoelectron microscopic study revealed the existence of GAL-containing synaptic vesicles in the SFO. These results suggest that the SFO has neural inputs involving GAL. The response to GAL is inhibitory, mediated at least in part by GalR1 and provides a plausible explanation for the opposite effects of ANGII and GAL seen in vivo on water intake and vasopressin release.

An outbreak of gastroenteritis in Osaka, Japan due to Escherichia coli serogroup O166:H15 that had a coding gene for enteroaggregative E. coli heat-stable enterotoxin 1 (EAST1)

In an outbreak of gastroenteritis on 23 July 1996, in Osaka, Japan, 54 of 91 persons who had attended a meeting the previous day became ill. Escherichia coli O166:H15 was isolated from stool specimens of patients (29/33, 88%). Laboratory tests for other bacterial pathogens and viruses were negative. The E. coli 0166 organisms did not adhere to HEp-2 cells in a localized, diffuse, or enteroaggregative manner. The organisms did not express known enterotoxigenic E. coli (ETEC) colonization factors. In polymerase chain reaction tests, the bacteria did not have coding genes for shigatoxin of enterohemorrhagic E. coli (EHEC), heat-labile, or heat-stable enterotoxin of ETEC, attachment and effacement (eaeA) of EPEC, or invasion (invE) of enteroinvasive E. coli (EIEC). Consequently, they could not be assigned to any of the recognized diarrhoeagenic groups of E. coli: EPEC, ETEC, EHEC, EIEC, enteroaggregative E. coli (EAggEC), or diffusely adhering E. coli. However, the organisms possessed the EAggEC heat-stable enterotoxin (EAST1) gene. To our knowledge, this is the first report of an outbreak caused by E. coli that did not have well-characterized virulence genes other than EAST1. The isolates showed the same DNA banding pattern in pulsed-field gel electrophoresis after digestion with the restriction enzymes XbaI or NotI. Three O166:H15 strains isolated from two sporadic cases and another outbreak during 1997-8 were distinct, indicating that multiple clones have spread already. We propose that diarrhoeal specimens should be examined for E. coli possessing the EAST1 gene.

No difference in the level of gastric mucosal cell apoptosis and proliferation in Helicobacter pylori-colonized p53 heterozygous knockout mice

BACKGROUND

We previously reported that attenuated epithelial apoptosis and enhanced proliferation in comparison with mice might link to the specific carcinogenesis in Mongolian gerbils and suggested that the difference in both strains might be due to a difference in genetic background. p53 is a well-known tumour suppressor gene, mutation of which is also known to be involved in gastric cancer formation.

AIM

The present study was designed to examine the level of gastric epithelial apoptosis and proliferation in p53 heterozygous knockout mice (p53+/-) colonized with Helicobacter pylori (Sydney strain: SS1).

METHODS

Female p53+/- mice and wild-type controls were orally inoculated with SS1 and the stomachs were examined 24 weeks later. DNA fragmentation was measured by levels of cytoplasmic mono- & oligo-nucleosomes as well as by the TUNEL method. Gastric mucosal proliferative activity was morphometrically evaluated from the PCNA-stained tissue specimens. Gastric mucosal myeloperoxidase (MPO) activity was measured to evaluate mucosal inflammation.

RESULTS

DNA fragmentation and the number of TUNEL-positive cells, as well as PCNA-positive cell number increased significantly in both groups of H. pylori-infected mice, suggesting that levels of apoptosis and proliferation may be independent of a deficiency of one p53 allele. MPO activity in p53+/- mice and wild-type controls increased to the same level.

CONCLUSION

Although H. pylori inoculation per se induces an increase in cell turnover in mice, heterozygous mutation of p53 did not significantly modify the balance in cell apoptosis and proliferation.

[Increasing fluoroquinolone low-sensitivity in enterotoxigenic Escherichia coli isolated from diarrhea of overseas travelers in Tokyo]

Drug resistance trends were investigated for 1,318 enterotoxigenic Escherichia coli (ETEC) isolated from overseas traveler's diarrheal cases in Tokyo during 1988-1999. A total of 1.6% (21 strains) were nalidixic-acid resistant and fluoroquinolones (NFLX, OFLX, CPFX, LVFX, TFLX, SPFX; FQ) low-sensitive (or low-level-resistant). None of the strains were high-level-resistant to FQ. The FQ low-sensitive strains were isolated in 1996 for the first time, and increased from 3.4% in 1996 to 15.8% in 1999. Countries visited by travelers with the FQ low-sensitive ETEC were India (16 cases), Nepal (3 cases), Cambodia (1 case), and Egypt (1 case). Drug resistance-patterns of the FQ low-sensitive strains, including other drugs (CP, TC, SM, KM, ABPC, ST, NA, and FOM) tested, varied among the 6 types. Among those, multidrug resistant strains accounted for 57.1% (12 strains). The enterotoxin producing types of strains were LT (4 strains), ST (10 strains), and both (7 strains). The serotypes of the strains were classified into 16 types. The quinolone resistance determining regions (QRDRs) of the gyrA genes of the FQ low-sensitive strains were sequenced. The mutations of a Ser to a Leu at position 83 (Ser-83-->Leu) was found in 19 strains, and Asp-87-->Tyr was found in 2 strains.

[The trends of Vibrio parahaemolyticus foodborne outbreaks in Tokyo: 1989-2000]

The total number of foodborne outbreaks due to Vibrio parahaemolyticus in Tokyo during the last 12 years between 1989 and 2000 were 710. The number of outbreaks in a year was 55 in 1989, 75 in 1990, and there was a gradual decrease to 24 outbreaks in 1993 which was the smallest number during those 12 years. After 1994, the number of outbreaks increased dramatically year by year until 1998 (107 outbreaks). Then they had decreased slightly to 74 in 1999, 65 in 2000. The monthly incidence of V. parahaemolyticus foodborne outbreaks showed a peak in August (44.2%) each year. In the last 12 years, 88.7% of V. parahaemolyticus foodborne outbreaks occurred during the 3 months between July and September, while 99.9% occurred between June and October. The most prevalent serotype of V. parahaemolyticus also changed, the most prevalent was O4:K4 in 1989, O4:K8 in both 1990 and 1991, O1:K56 in 1992, and O4:K8 from 1993 through 1995. Serotype O3:K6 became the most prevalent in 1996 and has remained so to date. In addition, the new serotype O4:K68 had also appeared in 1998. The number of outbreaks due to serotype O4:K68 followed that of O3:K6. Thus, the trends of V. parahaemolyticus foodborne outbreaks during the last 12 years in Tokyo showed various characteristics and dramatic changes in causal organisms.

Polaprezinc attenuates the Helicobacter pylori-induced gastric mucosal leucocyte activation in Mongolian gerbils--a study using intravital videomicroscopy

BACKGROUND

We previously demonstrated that Helicobacter pylori colonization evokes gastric mucosal inflammation and an extensive increase in lipid peroxides and glutathione in Mongolian gerbils. Zinc and its derivative, polaprezinc, have been reported to be potent antioxidants in gastric mucosa.

AIM

To examine the effect of polaprezinc on gastric mucosal oxidative inflammation in H. pylori-colonized Mongolian gerbils.

METHODS

Sixty-eight male Mongolian gerbils were orally inoculated with H. pylori (ATCC43504, 5 x 10(8) CFUs/gerbil; H. pylori group) and 35 gerbils were inoculated with the culture media (control group). Twenty-two gerbils in the H. pylori and 13 gerbils in the control group were fed with diets containing polaprezinc (0.06%, 100 mg/kg, 10 times the usual clinical dose) (H. pylori + polaprezinc group, polaprezinc group). The remaining gerbils were fed a standard laboratory chow diet. Neutrophil infiltration, assessed histologically and by the activity of myeloperoxidase, the contents of CXC-chemokine (GRO/CINC-1-like protein) and the contents of thiobarbituric acid-reactive substances, was evaluated in each group 12 weeks after the inoculation. Separately, gastric mucosal leucocyte activation and capillary perfusion were also assessed using intravital microscopy 2, 4, 8 and 12 weeks after the inoculation.

RESULTS

In all H. pylori-inoculated animals, the bacterial infection persisted throughout the experimental period. Gastric mucosal lesion formation in the H. pylori group was significantly inhibited in the H. pylori + polaprezinc group. Elevated levels of myeloperoxidase activity, GRO/CINC-1 and thiobarbituric acid-reactive substances in the H. pylori group at 12 weeks were attenuated significantly by polaprezinc treatment. Enhanced levels of venular leucocyte activation observed in the H. pylori group were attenuated significantly in the H. pylori + polaprezinc group during both the early phase (2 weeks) and late phase (12 weeks).

CONCLUSION

Polaprezinc inhibited H. pylori-associated gastric mucosal oxidative inflammation, including initial micro-vascular leucocyte activation, in Mongolian gerbils.

[Serovar-distribution and drug-resistance of Salmonella strains isolated from domestic and imported cases during 1995-1999 in Tokyo]

A total of 2,277 non-typhoidal Salmonella strains consisting of 1,807 domestic strains and 470 imported strains isolated from sporadic cases during 1995-1999 in Tokyo, were examined regarding their serovar-distibution and their drug-resistance. The serological typing results showed that the domestic strains were classified into 17 O-groups and 99 serovars, and the imported strains were classified into 12 O-groups and 58 serovars. Among the serovars identified, Salmonella serovar Enteritidis (S. Enteritidis), S. Thompson, S. Hadar, S. Infantis, S. Typhimurium, and S. Litchfield were predominant in the domestic strains, whereas S. Enteritidis, S. Anatum, S. Hadar, and S. Weltevreden were predominant in the imported strains. The drug-resistance test using 9 drugs (CP, TC, SM, KM, ABPC, ST, NA, FOM, and NFLX) showed that 34.0% of the domestic strains and 33.0% of the imported strains were resistant to any of the drugs examined. The serovars of a high resistant rate during this period were S. Blockley (100%), S. Hadar (96.6%), S. Typhimurium (63.6%), and S. Enteritidis (62.2%) in the domestic strains and S. Blockley (100%), S. Hadar (97.1%), S. Rissen (88.9%), S. Emek (83.3%), S. Panama (83.3%), and S. Typhimurium (77.8%) in the imported strains. Drug-resistance patterns of the resistant isolates varied to 60 types. Prevalent patterns recognized were SM, TC.SM, TC, TC.SM.KM.ST, TC.SM.KM, and CP.TC.SM.ABPC in the domestic strains and TC.SM, TC, NA, TC.SM.KM.NA, and TC.SM.NA in the imported strains.

[Increasing nalidixic-acid-resistance in Salmonella strains isolated from sporadic cases in Tokyo]

A total of 118 nalidixic-acid (NA)-resistant Salmonella strains consisting of 68 domestic strains and 50 imported strains isolated during 1988-1998 in Tokyo were examined regarding their annual incidence, serovars, drug-resistance patterns, and minimum inhibitory concentrations(MIC) to fluoroquinolones (NFLX, OFLX, ENX, and CPFX). NA-resistant strains accounted for 1.3% of all Salmonella (5,302 strains) isolated from domestic cases, and 2.5% of all Salmonella (1,981 strains) isolated from imported cases. The incidence of NA-resistant strains has increased since 1995, and it has been remarkable in imported cases. The results of the serotyping showed that the NA-resistant strains were classified into 25 serovars, excluding untypable strains. Among those, S. Enteritidis (21 strains), S. Blockley (13 strains), S. Litchifield (13 strains), S. Typhimurium (13 strains), S. Hadar (9 strains), and S. Virchow (8 strains) were predominant. Drug-resistance patterns of NA-resistant strains, including other drugs (CP, TC, SM, KM, ABPC, ST, FOM, and NFLX) tested varied among the 26 types. Among those, multidrug-resistant strains accounted for 61.9% (73 strains), and one strain among them was high-resistant to NFLX. MIC distribution of NA-resistant strains to fluoroquinolones showed that the ranges of all drugs were 4-128 times higher than NA-sensitive strains used for controls.

Obesity-sleep apnea (Pickwickian) syndrome: autopsy findings and a medicolegal review

A 24-year-old obese woman was found dead in her boyfriend's apartment in his absence. She had been admitted to the hospital six times previously because of diminished consciousness, respiratory failure, and pneumonia. A diagnosis of obesity-sleep apnea (Pickwickian) syndrome was made. An autopsy showed that she had an extremely small larynx, intra-alveolar hemorrhage, edema, pulmonary lymphocyte infiltration, and severe focal myocardial fibrosis. No fresh myocardial lesion, coronary arterial lesion, or findings of heart failure were seen. The woman's elder sister had also died of the same disease at the age of 23. The cause of death was diagnosed as respiratory failure and pneumonia with the sleep-apnea syndrome as the underlying cause of death. Although no autopsy reports of the sleep-apnea syndrome have been published in the field of forensic pathology, this syndrome is a predominant cause of sudden death in obese persons and could be a hidden cause of accidental death in such persons.

[Incidence of Salmonella serovar Hadar from sporadic cases in Tokyo, and drug resistance of isolates]

A total of 780 Salmonella serovar Hadar (S. Hadar) strains consisting of 601 domestic strains and 179 imported strains isolated in Tokyo, 1980-1998, were examined regarding their incidence and drug-resistance. Domestic strains accounted for 7.2% of all Salmonella (8,359 strains) isolated from domestic cases, and imported strains accounted for 4.4% of all Salmonella (4,083 strains) isolated from imported cases. A drug-resistance test using 9 drugs (CP, TC, SM, KM, ABPC, ST, NA, FOR, and NFLX) showed that 586 strains (97.6%) of the domestic strains and 175 strains (97.8%) of the imported strains were resistant to some of the drugs, excluding NFLX. Drugs with a high resistance rate were TC and SM for both groups. Drug-resistance patterns of the resistant strains varied among the 24 types. Among those, prevalent patterns recognized were TC.SM.KM (231 strains), TC.SM (205 strains), and TC.SM.KM.ABPC (65 strains) in the domestic strains, and TC.SM (135 strains) and TC (13 strains) in the imported strains.

Ethanol intake preceding Helicobacter pylori inoculation promotes gastric mucosal inflammation in Mongolian gerbils

BACKGROUND

Mongolian gerbils have been reported to be a suitable model for Helicobacter pylori-associated gastric mucosal injury, including gastric cancer. Although ethanol is known to be one of the harmful substances in the gastric mucosa, the relationship between ethanol and H. pylori infection remains unknown. The aim of the present study is to investigate the effect of ethanol treatment prior to H. pylori inoculation on associated gastric mucosal injury.

METHODS

Male Mongolian gerbils were used for the study. Helicobacter pylori was orally inoculated after 15 h fasting (Hp group). Thirty minutes prior to H. pylori inoculation, a group of gerbils was orally treated with 40% ethanol (20 mL/kg; E + Hp group). Another group of animals was treated either with H. pylori culture media alone (controls) or with 40% ethanol plus culture media (E group). Gerbils were killed 2, 4 or 12 weeks after H. pylori inoculation. Helicobacter pylori infection was confirmed by both histological examination and serological tests. Mucosal damage was evaluated histologically according to the modified Sydney system.

RESULTS

Although in the controls and E group no significant change to the gastric mucose was observed, persistent H. pylori infection was seen in the mucosa and mucosal leucocyte infiltration and severe epithelial damage was observed in the Hp and E + Hp groups after 4 weeks. The histological scores for polymorphonuclear cell infiltration and myeloperoxidase activity were higher in the E + Hp group at 4 weeks than in the Hp group (P < 0.05).

CONCLUSIONS

Ethanol intake preceding H. pylori inoculation could promote the progression of gastric mucosal inflammation in Mongolian gerbils.

[Study on the verotoxin-producing Escherichia coli--isolation of the bacteria from deer dung]

To identify the source and route of verotoxin-producing Escherichia coli (VTEC) infection in humans, we tried to isolate VTEC from fresh deer dung collected from free-range animals in two parks during the period from August 1997 to January 1998. The results are presented below. 1) VTEC were isolated from 21 of 200 deer dung samples (10.5%), consisting of 15 of 100 samples (15.0%) collected in park A and 6 of 100 samples (6.0%) collected in park B, suggesting that the incidence of VTEC isolation differs depending on location. 2) With respect to typing of verotoxin, the 21 isolated VTEC strains consisted of 10 strains (47.6%) as VT1 producer, 5 strains (23.8%) as VT2 producer, and 6 strains (28.6%) as double producer of both types. 3) With respect to serogroup of the isolated VTEC strains, 2 strains belonged to O128:H2.1 strain each belonged to the O8:H10, O128:H12, and O169:HUT groups. The remaining 16 strains failed to be identified as particular serotypes. Regarding local distribution of the serotype, in park A, 1 strain each belonged to the O128:H2, O8:H10, and O169:HUT groups. The remaining 12 strains did not clearly show particular serotypes. In park B, 2 strains belonged to O128:H2, and 4 strains failed to show particular serotypes. The remaining 1 strains showed autoagglutination. In conclusion, we isolated VTEC strains from deer that showed types of toxin and serogroups identical to those of human VTEC. Therefore, VTEC found in deer dung could well be a source of VTEC-infectious diseases in humans.

[Outbreak case caused by different colicin type of Shigella sonnei in a day nursery in Tokyo (1998)]

From October through December, 1998, person to person infection caused by Shigella sonnei had occurred in the day nursery in Hachioji-city Tokyo, and a total of 41 patients including 3 suspected cases and 3 carriers had been confirmed. Although one case was imported case which is one-year-old kindergarten child, the remaining was domestic case. Of patients, 33 cases (80.5%) were a three-year-old kindergarten children and their families, accounting for 20 and 13 cases, respectively. From the data of symptom onset of patients, epidemic could distinguish to the former part and the later part. The recur or reinfection, and re-detection case was observed in the later part. Clinical symptom of the patients was diarrhea (100%), fever (80%) and abdominal cramps (70%), and LVFX for adult or FOM for child was used for the therapy. In the colicin typing test and the antibiotic susceptibility test for 9 reagents, almost isolates in the former part were type 0 and susceptible, and MBC for FOM ranged from 6.25 to 100 micrograms/ml, whereas those in the later part was type 2 and resistant for the TC, and showed highly MBC for FOM with 50 or 100 micrograms/ml. However, both isolates showed same patterns in plasmid profiles and DNA fingerprints by RAPD analysis. On the other hand, the strain from imported case was also colicin 0, but it was different as regards resistant for ABPC and ST and two genetic analysis.

[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).

[Strains of Shigella sonnei recently isolated in Tokyo]

A total of 341 Shigella sonnei strains consisting of 94 domestic strains and 247 imported strains isolated during 1990-1997 in Tokyo, were examined regarding their colicine-type, drug-resistance and ornithine-utilization. The colicine typing results showed that the domestic strains were classified into 7 types, and the imported strains were classified into 13 types. Among the colicine-types identified, 8-type, 0-type, 6-type and 12-type were predominant in the domestic strains, whereas 6-type, 0-type, 8-type, 9A-type and 12-type were predominant in the imported strains. The drug-resistance test using 9 drugs (CP, TC, SM, KM, ABPC, ST, NA, FOM and NFLX) showed that 89.4% of the domestic strains and 85.4% of the imported strains were resistant to some of the drugs except FOM and NFLX. Drugs with a high resistant rate were SM, TC and ST for both groups. Drug-resistance patterns of the resistant strains varied in 22 types. Among those, a triple drug-resistance type with TC.SM.ST was found in the most frequent pattern in both groups. The results of the ornithine-utilization test revealed that 28.7% of the domestic strains and 8.1% of the imported strains were negative. The ornithine-negative strains in the same source had a similar plasmid-profile, but generally there was no correlation between the different sources.

[Biochemical and molecular characterization of Salmonella ser. enteritidis phage type 1 isolated from food poisoning outbreaks in Tokyo]

Since the first outbreak in 1990, the incidence of Salmonella ser. Enteritidis (S. Enteritidis) phage type (PT) 1 food poisoning has gradually increased in Tokyo and has reached approximately 30% of the total S. Enteritidis outbreaks reported. To characterise these S. Enteritidis PT1 food poisoning, a total of 198 strains obtained from 44 outbreaks between 1990 and 1996 were examined for antimicrobial resistance, acid producibility from glycols (propylene and ethylene glycol) and plasmid DNA profiles. The 44 PT1 outbreaks analysed were further subdivided into 11 types by epidemiological markers. The most common patterns were type A (plasmid profile carrying only one plasmid (60 kb). SM and TC resistance and non producibility from glycols), and type B (plasmid profile carrying two plasmids (60 and 20 kb), SM resistance and no producibility from glycols) and were responsible for 21 (47.7%) and 15 (34.1%) outbreaks, respectively. In 11 of 44 outbreaks, strains carrying identical epidemiological markers were isolated both from patients and vehicle foods, environments, and/or food-handlers. Similar to PT4 and PT34 outbreaks reported in Japan, egg and egg-related foods were also suspected in 8 of these 11 outbreaks. Of interest, chicken which were not pointed out in PT4 and PT 34 outbreaks was also suspected as a vehicle of transmission in two outbreaks.

[Prevalence and serotypes of verocytotoxin-producing Escherichia coli (VTEC) isolates from dairy cattle]

To clarify the source of infection and route of transmission of Verocytotoxin-producing Escherichia coli (VTEC) in humans, we collected fresh feces from healthy dairy cattle reared in Hokkaido, Fukushima, Kanagawa and Okinawa prefectures between June 1996 and March 1997, and attempted to isolate VTEC. The results are described below. 1) VTEC was isolated from 68 (27.1%) of 251 fecal samples tested. VTEC was isolated from 14 (28.0%) of 50 in Hokkaido, 13 (26.0%) of 50 in Fukushima, 20 (39.2%) of 51 in Kanagawa and 21 (21.0%) of 100 in Okinawa. There were no difference in the prevalence among the prefectures. 2) Toxin type and serotype of 85 isolates were determined. Thirty-three isolaties (38.8%) were classified into VT1 toxin and VT2 toxin, respectively, and 19 isolates (22.4%) were classified as the strain that produces both VT1 and VT2 toxins. The toxin types of these isolates were divided by serotypes. The VT1-producing isolates were the most frequent among O111:H-. The VT2-producing isolates included O2:H12, O2:H29, O2:H-, O82:H8, O82:HUT, O153:H19, O153:H42 and O153:H-. Among the isolates producing both VT1 and VT2 toxins, O153:H19 was relatively frequent. Based on findings that many bacterial strains coinciding with toxin types and serotypes of human-derived VTEC isolated from dairy cattle, it was suggested that dairy cattle are closely related to VTEC infection in human as a source of infection.

Helicobacter pylori-associated gastric pro- and antioxidant formation in Mongolian gerbils

Helicobacter pylori colonized gastric mucosa is manifest in a significant neutrophil infiltration with an extensive level of oxyradical formation. Mongolian gerbil is one of the excellent models for H. pylori-infection. The present study was designed to investigate pro- and antioxidant formation in the stomach of H. pylori-positive gerbils. Fourteen male Mongolian gerbils (MGS/Sea) were orally inoculated with H. pylori (ATCC43504) (Hp group) and 15 gerbils were inoculated with the culture media (Control). H. pylori infection was confirmed by the serum anti-H. pylori IgG test. Each gerbil was evaluated 6 or 12 weeks after the inoculation. Neutrophil infiltration was assessed by the tissue MPO activity. Mucosal oxidative stress was evaluated by thiobarbituric acid-reactive substances (TBARS), total glutathione contents, glutathione peroxidase (GSHPx) activity and Cu-, Zn-superoxide dismutase (SOD) activity. In Hp group, the H. pylori was persistently infected until 12 weeks. The level of MPO activity was significantly higher in Hp group at 6 and 12 weeks. Although the levels of TBARS and total glutathione were within the same range as controls at 6 weeks, they were significantly increased at 12 weeks. However, GSHPx activity was significantly increased at 6 weeks, but became the same range with the controls at 12 weeks. SOD activity showed no significant increase in Hp group at 6 and 12 weeks. In conclusion, H. pylori inoculation induced gastric mucosal neutrophil activation and pro-oxidant formation and also increased total glutathione contents, one of the mucosal antioxidants in gerbils.

Effect of rebamipide on H. pylori-associated gastric mucosal injury in Mongolian gerbils

Helicobacter pylori colonized to gastric mucosa plays an important pathogenic role in gastric mucosal lesions. We previously reported that ethanol pretreatment promotes the extension of H. pylori-associated lesions. The present study was designed to examine the effect of rebamipide, a mucosal protective agent, on H. pylori-associated injury. Male Mongolian gerbils were orally inoculated with H. pylori; 30 min prior to inoculation, 40% ethanol was administered orally to these gerbils (Hp group). Controls were given 40% ethanol with culture medium (control group). Some gerbils in the Hp and control groups were fed rebamipide-containing diets, and the remaining gerbils received laboratory chow diets. H. pylori infection was evaluated by quantitative bacterial culture and histological examination. Although H. pylori was persistently detected and a remarkable mucosal leukocyte infiltration was observed in the Hp groups, the bacteria had disappeared naturally in 67% of the gerbils and mucosal damage was mitigated in the Hp + rebamipide group at four weeks after the inoculation. Collectively, rebamipide might play a role in inhibiting the level of H. pylori colonization and gastric lesion formation in Mongolian gerbils.

Prevalence of verotoxin-producing Escherichia coli harbored in the intestine of cattle in Japan

The production of verotoxin was examined in 2152 Escherichia coli isolates from 387 cattle in Japan from 1992 to 1994. The toxin was detected in 263 isolates from 94 cattle (detection rate: 24.3%). Verotoxin-producing E. coli (VTEC) was isolated from the cattle in 15 out of 17 prefectures, and the strains were divided into 33 serotypes. E. coli O157:H7 was isolated from 7 out of 387 cattle (detection rate: 1.8%) in four prefectures. These results suggest that VTEC is widely distributed in Japan and include a wide variety of serotypes.

[Biochemical and molecular characterization of Salmonella serovar enteritidis phage type 4 isolated from food poisoning outbreaks in Tokyo]

Since 1989, outbreaks of Salmonella ser. Enteritidis (S. Enteritidis) food poisoning have dramatically increased in Tokyo, and a total of 31 outbreaks has been reported in 1989. Twenty-one of these 31 outbreaks were caused by S. Enteritidis PT34, but 8 outbreaks were caused by S. Enteritidis PT4. After 1990 instead of SE PT34, food poisoning due to PT4, which was a very common phage type in the UK, has increased in Tokyo. Between 1989 and 1995, there were 144 food poisoning outbreaks caused by S. Enteritidis, and 64 of these outbreaks were by due to S. Enteritidis PT4, which was one of the main phage types in Tokyo. To characterize these strains of phage type (PT) 4,293 isolates from patients, and vehicle foods, eggs and environment in Tokyo were examined for plasmid DNA profiles, acid productivity from glycols (propylene and ethylene) and antimicrobial resistance patterns. Plasmid DNA was extracted by Kado's method, and analyzed by agarose gel electrophoresis. The acid productivity from propylene glycol or ethylene glycol were tested using Barsicow medium with 1% propylene glycol or ethylene glycol. Antimicrobial susceptibility to AM, CP, TC, SM, KM, NA, ST, FOM and NFLX was tested by the K-B disc method. The strains of PT4 were further subdivided into 9 types by those epidemiologic marker analysis. The prevalent pattern of PT4 strains was type A plasmid profile carrying only one plasmid (60 kb) and there were 2 kinds of antibiograms. One was SM resistant, while the other was susceptible. A total of 56 (87.5%) of 64 outbreaks was found to have been caused by these types of S. Enteritidis. Several kinds of egg-related foods were suspected as the vehicles of transmission among 24 outbreaks. Especially, in 5 outbreaks, S. Enteritidis strains were isolated both from patients and suspected food which were cooked with egg. This strongly suggests that these foods may be the potential source of infection in S. Enteritidis PT4 outbreaks.

Catalase and superoxide dismutase secreted from Helicobacter pylori

BACKGROUND

Previously, we have reported that toxic oxidants produced by activated neutrophils play a pivotal role in the development of Helicobacter pylori-induced gastric mucosal damage. Microorganisms, however, are characterized by their ability to produce a variety of antioxidant enzymes. This study is designed to measure the oxygen radical scavenging enzymes, such as catalase and superoxide dismutase (SOD), and urease in the supernatant of H. pylori (NCTC11637) suspension.

MATERIALS AND METHODS

H. pylori was inoculated on a sheep blood agar plate and harvested. Bacterial suspensions (10(9) cfu/ml phosphate buffer) were washed twice and incubated at 37 degrees C for 1, 2, 12, and 24 hours or were sonicated in ice. Their supernatants were obtained by centrifugation and filtration. SOD activity was measured spectrophotometrically by the cytochrome c method. Catalase activity was assayed by the fall in absorbance at 240 nm as H2O2 is degraded. Urease activity was determined by measuring the release of ammonia using Berthelot reaction.

RESULTS

Activities of both SOD and catalase were detected in the supernatants of 1-hour microaerophilic incubation. Their activities were almost constant in 4-, 12-, and 24-hour microaerobic incubation or sonication. Urease activity was increased dramatically in proportion to the period of microaerobic incubation.

CONCLUSION

Although H. pylori possesses antioxidant as a constitutive compartment, the magnitude of its secretion was below the detectable level. It is not likely that SOD and catalase play a significant role for scavenging the oxidants from injured gastric mucosa, such as infiltrated leukocytes.

Influence of substituent of direct dye having bisphenylenebis(azo) skeletal structure on structure of nascent cellulose produced by Acetobacter xylinum [I]: different influence of direct red 28, blue 1 and 15 on nascent structure

The difference of influence of a certain kind of direct dye on the structure of nascent microbial cellulose was examined, with Direct Red 28 have a biphenylenebis(azo) skeletal structure; Direct Blue 1 having two hydroxyl, two methoxy and two sulfonate groups more than Direct Red 28; and Direct Blue 15 whose sulfonate groups position are different compared to Direct Blue 1. It became clear that the product in the presence of a direct dye (in particular, Direct Red 28) has the structure in which the dye molecule is included between the monolayer in the cellulose sheets corresponding to the (110) plane of microbial cellulose. On the other hand, the structure of the product in the presence of Direct Blue 1 and 15 contains conceived cellulose II structure which occurred due to be removal of dye during the rinsing process as a result of larger hydrophilicity than its affinity toward cellulose. Solid state 13C NMR and deuteration-IR measurements showed that the product in the presence of direct dye is in a noncrystalline state, although X-ray measurements indicated that they are in a crystalline state. These results support the inclusion of a dye between the (110) planes. Solid state 13C NMR and deuteration-IR reveal that the crystal structure of cellulose regenerated from the product in the presence of Direct Red 28 is similar to cellulose IVI, while that from each Direct Blue 1 and 15 product is cellulose II. The difference of the influence of the former and the latter on the nascent cellulose seemed to be caused mainly by the number of sulfonate groups, although the influence of hydroxyl and methoxy groups is not clear at present.

[Evaluation of a latex agglutination method for detecting and characterizing verotoxin (VT) produced by Escherichia coli]

The detection of VT produced by Escherichia coli is very important for the identification of verotoxin-producing Escherichia coli (VTEC). The latex agglutination reagents (Denka Seiken Co. Ltd, Tokyo) which was developed to detect VT was compared with the vero cell bioassay or polymerase chain reaction method. A total 147 VT-positive strains (109 serotype O157:H 7/- and 38 non-O157 serotype) and 31 VT-negative strains which were isolated from human were investigated. In addition, a total of 79 VT-positive strains (14 serotype O157:H7/- and 65 non-O157 serotype) and 79 VT-negative strains which were isolated from animals were also examined. The latex agglutination assay for the human isolates showed the 100% sensitivity, specificity and agreement. The assay for the animal isolates showed 94.9% sensitivity, 100% specificity and 97.5% agreement. Although 4 of 8 strains isolated from swine which produce VT2 variant toxin (VT2e) failed in detecting verotoxin by latex agglutination assay, VT2e was not related to human infections. We conclude that this latex agglutination reagent is highly sensitive and specific for detecting and characterizing VT of E. coli. The method is reliable, easy to perform at any laboratories.

[Serological diagnosis of enterohaemorrhagic Escherichia coli(EHEC) infection by passive hemagglutination assay]

The passive hemagglutination(PHA) assay was developed to diagnose enterohaemorrhagic Escherichia coli(EHEC) infections serologically and was evaluated for the utility. The PHA assay was done using formalinized sheep erythrocytes sensitized with 2 kinds of antigens; soluble native and heat-treated antigens, by a microtiter method. A total of 63 serum samples from 33 HUS patients and 30 sporadic hemorrhagic colitis were subjected to the assay. For the control, 30 serum samples from 20 healthy adults and 10 healthy children were used. Thirty-two of 33 HUS patients had the antibody against soluble native antigen and/or heat-treated antigen of EHEC O157. These response was also observed in 14 HC cases with stool culture positive for EHEC O157. Good antibody response was observed against soluble native antigen than that against heat-treated antigen. The PHA titers distributed between 1:100 and 1:8,100 were observed in the samples taken in about 1 week or more after the onset of diarrhea, and the higher titer were observed in HUS patients than in HC patients. All of control sera were negative. The PHA assay described here is highly sensitive, simple and rapid method, and is recommended for the serological diagnosis of EHEC infections.

[Evolution of susceptibilities of Campylobacter jejuni isolated from diarrhoeal cases to fluoroquinolones in Tokyo]

Recently, the increase in the number of resistant strains of Campylobacter jejuni to fluoroquinolone has been reported in European countries. We also studied antimicrobial susceptibilities of 600 clinical isolates of Campylobacter jejuni isolated during a 6 year period from 1989 through 1994 in four Tokyo Metropolitan Hospitals. The susceptibility to 6 antimicrobial agents, norfloxacin (NFLX), ofloxacin (OFLX), ciprofloxacin (CPFX), nalidixic acid (NA), erythromycin (EM) and tetracycline (TC) were examined. The overall resistant rates were as follows: NFLX, 45 strains (7.5%); OFLX, 45 strains (7.5%); CPFX, 44 strains (7.3%); NA, 62 strains (10.3%); EM, 4 strains (0.6%) and TC, 259 strains (43.2%). The number of resistant strains to fluoroquinolones and NA has increased significantly since 1993 in Japan, but the susceptibility to erythromycin has still remained the same level during the past 6 years. The susceptibility to TC was variable, and MICs gave a bimobal distribution, as pointed out previously. The resistance pattern of NFLX, OFLX, CPFX and NA were observed most frequently in those isolates.

[Detection of the trh gene in Vibrio parahaemolyticus isolated from overseas travellers' diarrhea and their biochemical characteristics]

A total of 478 Vibrio parahaemolyticus strains isolated from overseas travellers' diarrhea during the last 7 years of 1989 to 1995 were examined for the production of Kanagawa hemolysin by reversed passive latex agglutination (RPLA) test. Three hundred-seventy (77.4%) out of 478 strains were positive for Kanagawa hemolysin, whereas 108 strains were weakly positive or negative. For those Kanagawa hemolysin-weakly positive or negative strains, the tdh and trh genes associated with the production of TDH (thermostable direct hemolysin) and TRH (TDH-related hemolysin), respectively, were studied by the polymerase chain reaction method. The trh gene was detected in 98 (90.7%) out of 108 strains. In 35 strains belonging to 13 serotypes such as O3: K6, O1:K33, O3:K59, the trh gene alone was detected. On the other hand, both trh and tdh genes were detected in 63 strains of 17 serotypes including O1:K69, O3:K72, O6:K46. Among the strains of 4 serotypes including O1:K56, O1:KUT, O3:KUT and O5:KUT, two types of the trh positive alone and the trh and tdh positive were observed. Of interest, all of the 98 trh-positive strains were positive for the urease hydrolysis, whereas all Kanagawa hemolysin-positive strains were not. Furthermore, the strains of serotype O6:K18 (4 strains) were positive for the fermentation of dulcitol, and the strains of serotype O1:K1 (5 strains) were indole negative. These characteristics of the strains were completely different from those of typical V. parahaemolyticus strains.

[Characterization of Salmonella ser. enteritidis phage type 34 isolated from food poisoning outbreaks in Tokyo by epidemiological makers]

Since 1989, outbreaks of Salmonella ser. Enteritidis food poisoning has dramatically increased in Tokyo, and a total of 95 outbreaks has been reported between 1989 and 1993. As the results of examination of phage type by the method of Ward, et al., strains isolated from 31 (32.6%) of 95 outbreaks were phage type 34 which is a very rare type in Europe and America. To characterize these unique strains of phage type (PT) 34, 302 isolates obtained from patients and vehicle foods of the outbreaks, eggs and environments in Tokyo were examined for plasmid DNA profiles and antimicrobial resistance patterns. Plasmid DNA was extracted by the Kado's method, and analysed by agalose gel electrophoresis. Antimicrobial susceptibility was tested for CP, TC, SM, KM, ABPC, NA, SXT, FOM and NFLX by the K-B disc method. The strains of PT 34 were further subdivided to 4 types by plasmid profile and antibiogram. The prevalent pattern of PT 34 strains was type plasmid profile which carried 2 different plasmids (> 250 and 60 kb) and was streptomysin-resistant. A total of 28 (90.3%) of 31 outbreaks were found to be caused by this specific type of Salmonella ser. Enteritidis. Several kinds of egg-related foods were suspected for the vehicles of transmission among 12 outbreaks. Especially, in 5 outbreaks, this specific type (type B plasmid profile and streptomysin resistant) of Salmonella ser. Enteritidis strains were isolated both from patients and incriminated food which were cooked with eggs. The phase type of Salmonella ser. Enteritidis strains isolated from raw egg and poultry or environmental specimens from poultry farm showed that the prevailing phage types were almost the same as those of foods poisoning outbreaks. This strongly suggests that these foods may be considered as a source of infection in Salmonella ser. Enteritidis outbreaks.

[Analysis of verotoxin-producing Escherichia coli (O157:H7) strains isolated in the Fukuoka area in 1994 by pulsed-field gel electrophoresis]

Nine verotoxin-producing Escherichia coli O157:H7 strains were isolated from 9 pediatric patients with sporadic enteritis between July and September 1994 at four clinics in the Fukuoka area. The patients included two families with two cases each. These strains were analyzed by pulsed-field gel electrophoresis for Xba I-digested DNA fragments. The restriction patterns were identical between each two strains within the two family outbreaks, but different among the seven strains of the distinct seven sporadic cases. It is strongly suggested that the seven sporadic cases were infected through distinct sources, and that the two family cases were due to a common source of infection or person to person infection.

Major enteropathogenic bacteria isolated from diarrheal patients in Bolivia: A hospital-based study

A total of 1,234 fecal samples from diarrhea cases were examined for etiological bacterial agents at medical facilities in La Paz and Sucre, Bolivia. Eighty strains of Shigella spp., 39 strains of Salmonella spp., 29 strains of Vibrio cholerae, and 222 strains of enteropathogenic Escherichia coli (139 EPEC, 55 ETEC, 29 EIEC, and 1 EHEC) were isolated. With regard to the serovars of Shigella, S. flexneri 2a, 3a, and 1b were predominant. In the case of Salmonella, S. enteritidis was the most common, followed by S. typhi, S. poona, and S. paratyphi B. Out of 29 cholera strains, 25 belonged to biovar El Tor, serovar Ogawa while the remaining 4 were serovar Inaba. Among 55 strains of ETEC serotypes, 5 showed ST producers but none showed LT producers. Likewise, among 55 strains of enterohemorrhagic serotypes, only one strain (O157:H7) produced verocytotoxin (VT 2). The results of drug sensitivity tests revealed the predominance of Shigella, EPEC, and ETEC strains resistant to aminobenzil-penicillin (ABPC) and trimethoprim. Since diarrheal patients in Bolivia are treated mainly with ABPC or sulfamethoxazole/trimethoprim (SXT) and rarely with gentamicin, kanamycin, or other drugs, it is possible that ABPC- and SXT-resistant strains will increase and persist in the near future.

Rebamipide, a novel antiulcer agent, attenuates Helicobacter pylori induced gastric mucosal cell injury associated with neutrophil derived oxidants

The effect of rebamipide, a novel antiulcer compound, on Helicobacter pylori activated neutrophil dependent in vitro gastric epithelial cell injury was investigated. Luminol dependent chemiluminescence (ChL), which detects toxic oxidants from neutrophils exhibited a 12-fold increase when the bacterial suspension of H pylori was added to the isolated human neutrophils. This change was significantly attenuated by rebamipide at a concentration less than 1 mM, showing that rebamipide may inhibit oxidant production from H pylori elicited neutrophils. To assess whether rebamipide attenuates gastric mucosal injury, we tested its inhibitory action on H pylori induced gastric mucosal damage associated with neutrophils in vitro. Rabbit gastric mucosal cells were monolayered in culture wells and coincubated with human neutrophils and H pylori, and the cytotoxicity index was then calculated. Cultured gastric cells were significantly damaged when they were incubated with human neutrophils activated by H pylori. This cellular damage was attenuated by rebamipide in a dose-dependent manner. Furthermore, spectrophotometrical measurement showed that rebamipide (1 mM) inhibits urease activity by 21.7%. As monochloramine (an oxidant yielded by reaction of neutrophil derived chlorinated oxidant and ammonia) is proposed as an important toxic molecule in this model, the current findings suggest that the preventive effect of rebamipide on H pylori elicited neutrophil induced gastric mucosal injury may result from its inhibitory actions on the neutrophilic oxidative burst as well as H pylori derived urease activity.

Verotoxin induces hemorrhagic lesions in rat small intestine. Temporal alteration of vasoactive substances

E. coli O157:H7 produces a cytotoxin active against Vero cells that has been termed verotoxin. In this study, we demonstrated that local intraarterial injection of verotoxin induced a decrease in blood flow and an increase in hemorrhagic lesions in rat small intestine. Significant increases in the area of hemorrhagic lesions were observed at 120 min after verotoxin injection. These lesions were produced by either verotoxin 1 or 2, but verotoxin 2 produced more extensive lesions. The temporal alteration of vasoactive substances in microcirculatory beds was determined after the administration of culture filtrate of E. coli O157:H7. Tissue-type plasminogen activator activity in regional plasma was significantly elevated as early as 30 min, suggesting that local fibrinolytic activation mediated by microvascular endothelium occurred. There was also early elevation of platelet-activating factor content in the ileal mucosa and its level remained significantly elevated thereafter. Intestinal blood flow, as determined by a laser Doppler flowmeter, started to decrease at about 45 min. The platelet-activating factor antagonist CV6209 was shown to attenuate the decrease in blood flow as well as the development of hemorrhagic lesions, demonstrating that platelet-activating factor is an important mediator for the microcirculatory damage. Accumulation of neutrophils demonstrated by myeloperoxidase activity in the intestinal mucosa and overproduction of oxygen-radicals from neutrophils of the mesenteric veins determined by the luminol-dependent chemiluminescence assay were observed at 60 min, corresponding with the decreased blood flow. Platelet-activating factor may be closely involved in the process of leukocyte accumulation and increased oxygen radical generation, because CV6209 also significantly attenuated these changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Serodiagnosis by passive hemagglutination test and verotoxin enzyme-linked immunosorbent assay of toxin-producing Escherichia coli infections in patients with hemolytic-uremic syndrome

Eight cases of hemolytic-uremic syndrome in which no pathogens were isolated were diagnosed serologically by a passive hemagglutination assay and a verotoxin (VT; Shiga-like toxin) enzyme-linked immunosorbent assay (ELISA). The passive hemagglutination assay employed formalinized sheep erythrocytes sensitized with soluble native antigen or heat-treated antigen (lipopolysaccharide [LPS]) from Escherichia coli O26, O111, O128, and O157 or flagellar antigen of nine different H serogroups of E. coli: H2, H7, H8, H10, H11, H12, H18, H19, and H25. All patients had antibodies against the native antigen and/or the LPS of E. coli O157, but positive agglutination with H7 was observed only in one patient. In the VT-ELISA with plates coated with purified VT 1 or VT 2, antibody against VT 2 was observed in the sera of five of six patients examined, but none of the patients possessed VT 1 antibody. These results indicate that the causative pathogen in these eight hemolytic-uremic syndrome cases is likely to be VT-producing E. coli O157. The passive hemagglutination assay described here is a very sensitive, simple, and rapid method. This assay is highly recommended for the serological diagnosis of VT-producing E. coli infections, particularly in patients infected by serogroup O157 strains. Furthermore, the VT-ELISA is useful in studying the role of VT in hemolytic-uremic syndrome.

[Contamination of healthy livestock with verocytotoxin producing Escherichia coli (VTEC), the first isolation from goats in Japan]

As part of the investigation on the source and route of infection with Verocytotoxin producing Escherichia coli (VTEC) in human beings, isolation of VTEC was attempted using fresh feces collected from healthy livestock (cattle, swine and goat) raised in Sagamihra, Yokohama and Hiratsuka cities from October, 1991 to March, 1992. VTEC could be isolated from 1 (1.0%) of 105 swine, 2 (3.6%) of 55 cattle and 2 (15.4%) of 13 goats. VTEC was isolated for the first time from goats in Japan. The combinations of the serotype and toxin type of the isolated strains were O116:H21 (VT2) and O163:H19 (VT2) for those isolated from the cattle, OUT:H19 (VT2vp) for that from the swine and OUT:H21 (VT1) for those from the goats. Since VTEC isolated from the cattle and goats were found to produce VT of the same serotypes as human VTEC, domestic animals were considered to be involved as a source of VTEC infection in human beings.

Immunological specificity of Helicobacter pylori urease and identification by immunological detection of its specific urease

Helicobacter pylori urease was recovered as a single peak by DEAE-Sepharose column chromatography and Sephacryl S-200 gel filtration. The purified urease was obtained by fast protein liquid chromatography using a Mono Q column. The purified urease preparation gave a single band in polyacrylamide gel disc electrophoresis. Latex particles were sensitized with anti-urease immunoglobulin. The sensitized latex particles were agglutinated with the purified urease and by cell sonicates obtained from 55 strains of H. pylori which were isolated from the gastric mucosa of patients with gastric and duodenal disorders, while they did not react with those obtained from related bacteria known to be urease producers, such as Helicobacter mustelae and urease- positive "Campylobacter lari variants", or by urease of some strains of Enterobacteriae. We have developed a specific and sensitive method for detecting the urease by using the reversed passive latex agglutination technique, in order to identify of the organism.

Invasive strains of Escherichia coli belonging to serotype O121:NM

Ten strains of Escherichia coli isolated from 10 travellers with sporadic diarrhea who were returning to Tokyo, Japan, from abroad were found to be of serotype O121:NM and were positive in the Serény test for invasiveness; this suggests that this serotype can cause a shigellosis-like illness in humans. The E. coli O121:NM strains were positive in the cell invasion test in HeLa cells. Analysis of the plasmid content of these strains showed that they contained a high-molecular-mass plasmid of 120 to 140 MDa which has been associated with invasiveness and were positive in an enzyme-linked immunosorbent assay for detection of the virulence plasmid-encoded proteins of Shigella spp. and enteroinvasive E. coli.

Biosynthesis of curdlan from culture media containing 13C-labeled glucose as the carbon source

13C-Labeled curdlans were biosynthesized by Agrobacterium sp. (ATCC 31749) from culture media containing D-(1-13C)glucose, D-(6-13C)glucose, or D-(2-13C)glucose as the carbon source, and their structures were analyzed by 13C NMR spectroscopy. The labeling was mainly found in the original position, that is, C-1, C-6, or C-2, indicating direct polymerization of introduced glucose. In addition, C-3 in curdlan obtained from D-(1-13C)glucose, C-1 in curdlan obtained from D-(6-13C)glucose, and C-1 and C-3 in curdlan obtained from D-(2-13)glucose were labeled. From analysis of this labeling, the biosynthesis of curdlan was interpreted as involving five routes: (1) direct synthesis from glucose; (2) rearrangement (1-13C-->3-13C); and (3) isomerization (6-13C-->1-13C) of cleaved trioses by the Embden-Meyerhof pathway, followed by neogenesis of glucose and formation of curdlan; (4) from fructose 6-phosphate formed in the pentose cycle (2-13C-->1-13C, 3-13C); and (5) neogenesis of glucose from fragments produced in various pathways of glycolysis. The 13C-labeling at C-6 and C-2 in the starting glucoses is well preserved in the C-6 carbon and the C-1 to C-3 carbons, respectively, in the curdlan produced.

[Epidemiology of sporadic pediatric enteritis patients due to verotoxin-producing Escherichia coli]

We tried to isolate verotoxin-producing Escherichia coli (VTEC) from 323 sporadic pediatric enteritis patients who came to three clinics in the Fukuoka area. We used the sorbitol-MacConkey medium for the isolation of VTEC O157:H7. For non-O157 VTEC strains we used the V1/PECS method. VT/PECS method was applied. VTEC strains were isolated from three patients (0.9%). None of the patients were seriously, ill or developed the hemolytic uremic syndrome. The three patients were all seen in the summer season, July and August. O157:H7 strains were isolated from two patients, and O145:NM from one. This study showed that sporadic enteritis cases due to VTEC exist in the Fukuoka area. In the future a rapid and easy method for the detection of VT or VTEC should be developed and commercialized to proceed with epidemiological studies of VTEC infections throughout Japan.

Detection of verocytotoxin from stool and serological testing of patients with diarrhea caused by Escherichia coli O157 : H7

The detection of verocytotoxin (VT) in stool and measurement of antibodies against VT and three antigens (unheated-antigen, LPS, and flagellin) of Escherichia coli O157 : H7 in the serum of patients with diarrhea were examined. Five of 14 inpatients during an outbreak had fecal VT2 in stool taken within 5 days of onset to hospitalization. Among these 5, 3 of them also had fecal VT-producing E. coli (VTEC) serotype O157 : H7, whereas the other 2 did not. In the passive hemagglutination (PHA) test with formalinized sheep red blood cells sensitized with three VTEC O157 : H7 antigens, 49 (74.2%) of 66 outbreak patients and 3 of 3 sporadic cases had antibodies against both or one of unheated-antigen and LPS of E. coli O157, but none had antibody against flagellin. In addition, anti-VT2 antibody was demonstrated in serum samples from 15 (94%) of 16 inpatients and 2 (4%) of 50 outpatients in an outbreak by a VT-enzyme-linked immunosorbent assay (VT-ELISA). These results showed that serological assay particularly for antibodies against VT and unheated-antigen or LPS of VTEC O157 may provide a useful tool for diagnosis of infection with VTEC O157.

[An outbreak of gastroenteritis due to group C rotavirus in Tokyo]

In April 1991, an outbreak of acute gastroenteritis due to group C rotavirus occurred at an elementary school in Tokyo. Fifty-one (13%) of 393 students became ill. The main clinical symptoms were diarrhea (100%), abdominal pain (68%) and vomiting (56%). No enteropathogenic bacteria were found in the fecal specimens. However, the virus particles morphologically indistinguishable from conventional rotavirus were detected in 6 of 11 fecal specimens by electron microscopy. Immune electron microscopy showed that these virions aggregated with anti-group C rotavirus serum. The RNA pattern of the virus particles involved in this outbreak showed a pattern similar to that of typical group C rotavirus on polyacrylamide gel electrophoresis.