Growth and Survival of Escherichia albertii in Food and Environmental Water at Various Temperatures

Escherichia albertii is an emerging foodborne pathogen that causes diarrhea. E. albertii has been isolated from various foods, including pork and chicken meat, and environmental waters, such as river water. Although many food poisoning cases have been reported, there have been insufficient analyses of bacterial population behaviors in food and environmental water. In this study, we inoculated 2-5 log CFU of E. albertii into 25 g of pork, chicken meat, Japanese rock oyster, Pacific oyster, and 300 mL of well water and seawater at 4°C, 10°C, 20°C, and 30°C, and analyzed the bacterial population behavior in food and environmental water. After 3 days at 4°C, the population of E. albertii strain EA21 and EA24 in foods maintained approximately 4 log CFU/25 g. After 3 days at 10°C, the population of E. albertii strains in pork and oysters maintained approximately 4 log CFU/25 g, and that in chicken meat increased to approximately 5-6 log CFU/25 g. After 2 days at 20°C, E. albertii strains grew to approximately 6-7 log CFU/25 g in pork and chicken meat, and E. albertii strain EA21 but not EA24 grew to 4.5 log CFU/25 g in Japanese rock oyster, E. albertii strain EA21 but not EA24 slightly grew to 3.1 log CFU/25 g in Pacific oyster. After 1 day at 30°C, E. albertii strains grew to approximately 7-8 log CFU/25 g in chicken meat and pork, grew to approximately 4-6 log CFU/25 g in Japanese rock oyster, and 6-7 log CFU/25 g in Pacific oyster. These results suggest that E. albertii survives without growth below 4°C and grew rapidly at 20°C and 30°C in foods, especially in meat. E. albertii strains did not grow in well water and seawater at 4°C, 10°C, 20°C, and 30°C. The population of E. albertii strains in well water and seawater decreased faster at 30°C than at 4°C, 10°C, and 20°C, suggesting that E. albertii has low viability at 30°C in environmental water.

Development of a Novel Real-Time Polymerase Chain Reaction Assay to Detect Escherichia albertii in Chicken Meat

Escherichia albertii is an emerging enteropathogen. Several foodborne outbreaks of E. albertii have been reported in Japan; however, foods associated with most outbreaks remain unidentified. Therefore, polymerase chain reaction (PCR) assays detecting E. albertii specifically and sensitively are required. Primers and probe for real-time PCR assays targeting E. albertii-specific gene (EA-rtPCR) was designed. With 74 strains, including 43 E. albertii strains and several of its close relatives, EA-rtPCR specifically amplified E. albertii; therefore, the sensitivity of EA-rtPCR was then evaluated. The detection limits were 2.8 and 2.0-3.2 log colony-forming unit (CFU)/mL for E. albertii culture and enriched chicken culture inoculated with the pathogen, respectively. In addition, E. albertii was detected from 25 g of chicken meat inoculated with 0.1 log CFU of the pathogen by EA-rtPCR. The detection of E. albertii from chicken meat by EA-rtPCR was also evaluated by comparing with the nested-PCR assay, and 28 retail chicken meat and 193 dissected body parts from 21 chicken carcass were tested. One and three chicken meat were positive in the nested-PCR assay and EA-rtPCR, respectively. Fourteen carcasses had at least one body part that was positive for EA-rtPCR, and 36 and 48 samples were positive for the nested-PCR assay and EA-rtPCR, respectively. A total of 37 strains of E. albertii were isolated from seven PCR-positive samples obtained from six chicken carcass. All E. albertii isolates harbored eae gene, and were classified as E. albertii O-genotype (EAOg)3 or EAOg4 by EAO-genotyping. The EA-rtPCR developed in this study has potential to improve E. albertii detection in food and advance research on E. albertii infection.

[Evaluation of the Capacity to Produce Histamine by Histamine-Producing Bacteria during Storage at 10℃]

Histamine is produced from histidine using histidine decarboxylase of histamine-producing bacteria. However, associated histamine food poisoning demands microbiological controls. Furthermore, studies reported that histamine production by histamine-producing bacteria is affected by temperature. Therefore, to prevent histamine food poisoning, it is desirable to store foods below 4℃. However, it is challenging to maintain the storage temperature of food substances in refrigerators constantly below 4℃. Thus, we investigated histamine production capacity using seven histamine-producing bacterial strains under storage at 10℃, a more reasonable cold storage condition. Subsequently, we examined the variation of histamine production in buffers, the correlation between bacterial density and histamine production quantities, and the growth rate in broths. Results showed that similar levels of histamine were produced in buffers even after 5 days of storage under certain conditions in which histamine-producing bacteria did not grow. Moreover, bacterial density was proportional to histamine production, and the coefficient of determination was more than 0.97, and the bacterial density required to produce 200 μg/mL of histamine during storage at 10℃ was calculated to be 4×10⁷-4×10⁸ CFU/mL. When the initial bacterial density was 10²-10³ CFU/mL, psychrophilic bacteria required 2 or 3 days and mesophilic bacteria required more than 4 days to grow above 10⁷ CFU/mL. The above results suggest that understanding the capacity of histamine-producing bacteria to produce histamine and its growth rate in foods is important for the prevention of histamine food poisoning.

Detection of Escherichia albertii in Retail Oysters

ABSTRACT

Escherichia albertii is an emerging foodborne pathogen. Owing to its distribution in river water, it is important to determine the presence of E. albertii in aquaculture-related foods. In this study, we investigated the distribution of E. albertii in retail oyster samples. A total of 427 raw oyster samples (385 Pacific oysters and 42 Japanese rock oysters) were enriched in modified Escherichia coli broth (mEC) or mEC supplemented with novobiocin (NmEC) at 42°C. The cultures were used for E. albertii-specific nested PCR assay, as well as for E. albertii isolation using deoxycholate hydrogen sulfide lactose agar (DHL), DHL supplemented with rhamnose and xylose, and MacConkey agar supplemented with rhamnose and xylose. The population of E. albertii in nested PCR-positive samples was determined using the most-probable-number (MPN) method. E. albertii isolates were subjected to biochemical and genetic characterization. E. albertii was detected in 5 (1.6%) of 315 Pacific oyster samples (one piece each), 2 (2.9%) of 70 Pacific oyster samples (25 g each), and 2 (4.8%) of 42 Japanese rock oyster samples procured from four geographically distinct regions. A total of 64 E. albertii strains were isolated from eight of the nine nested PCR assay-positive oyster samples, and the MPN value was under the detection limit (<3 MPN/10 g). A specific season or month for detecting E. albertii was not observed in this study, suggesting that the pathogen is present in seawater. All the E. albertii isolates, except one, were positive for the virulence factor eae, indicating that these isolates have the potential to infect humans.

HIGHLIGHTS

Evaluating Methods for Detecting Escherichia albertii in Chicken Meat

ABSTRACT

Escherichia albertii is an emerging foodborne pathogen. The source of the E. albertii infection in most foodborne outbreaks is unknown because E. albertii is difficult to isolate from suspected food or water. E. albertii has a broad host range among birds and can be isolated from chicken meat. In this study, PCR assay, enrichment, and isolation conditions for detecting E. albertii in chicken meat were evaluated. The growth of 47 E. albertii strains isolated in Japan between 1994 and 2018 and a type strain was evaluated in modified EC broth (mEC) and mEC supplemented with novobiocin (NmEC) and on media containing carbohydrates. The enzyme used for the nested PCR, the enrichment conditions, the most-probable-number (MPN) method, and agar media were also evaluated with chicken meat. To distinguish E. albertii from presumptive non-E. albertii bacteria, desoxycholate hydrogen sulfide lactose agar (DHL), MacConkey agar (MAC), and these agars supplemented with rhamnose and xylose (RX-DHL and RX-MAC, respectively) were used. All E. albertii strains grew in mEC and NmEC at both 36 and 42°C and did not utilize rhamnose, sucrose, or xylose. Both the first and nested PCRs with TaKaRa Ex Taq, which was 10 to 100 times more active than the other enzymes, produced positive results in enrichment culture of 25 g of chicken meat inoculated with >20 CFU of E. albertii and incubated in mEC and NmEC at 42°C for 22 ± 2 h. Thus, the first PCR was sensitive enough to detect E. albertii in chicken meat. The MPN values in mEC and NmEC were 0.5- and 2.3-fold higher than the original inoculated bacterial levels, respectively. E. albertii in chicken meat was more efficiently isolated with enrichment in NmEC (70.1 to 100%) and plating onto RX-DHL (85.4%) and RX-MAC (100%) compared with enrichment in mEC (53.5 to 83.3%) and plating onto DHL (70.1%) and MAC (92.4%). Thus, optimized conditions for the surveillance of E. albertii contamination in food and investigations of E. albertii outbreaks, including the infectious dose, were clarified.

HIGHLIGHTS

An interlaboratory study on the detection methods for enterotoxigenic Escherichia coli in vegetables using enterotoxin gene screening and selective agars for ETEC-specific isolation

Enterotoxigenic Escherichia coli (ETEC) causes acute diarrhea and is transmitted through contaminated food and water; however, systematic procedures for its specific detection in foods have not been established. To establish an efficient detection method for ETEC in food, an interlaboratory study using ETEC O148 and O159 as representative serogroups was first conducted with 13 participating laboratories. A series of tests including enrichment, real-time PCR assays, plating on selective agars, and concentration by immunomagnetic separation followed by plating onto selective agar (IMS-plating methods) were employed. This study particularly focused on the detection efficiencies of real-time PCR assays for enterotoxin genes (sth, stp, and lt), IMS-plating methods, and direct plating onto sorbitol MacConkey agar and CHROMagar STEC medium, supplemented with tobramycin, which is a novel modification in the preparation of a selective agar. Cucumber and leek samples inoculated with ETEC O148 and O159, either at 4-7 CFU/25 g (low levels) or at 21-37 CFU/25 g (high levels) were used as samples with uninoculated samples used as controls. At high inoculation levels, the sensitivities of sth, stp, and lt detection, direct-plating, and IMS-plating methods in cucumber inoculated with O148 and in both foods inoculated with O159 were 100%. In leek inoculated with high levels of O148, the sensitivities of sth, stp, and lt detection, direct-plating, and the IMS-plating method were 76.9%, 64.1%, and 74.4%, respectively. At low inoculation levels, the sensitivities of sth, stp, and lt detection, direct plating, and IMS-plating method in cucumber inoculated with O148 and in both foods inoculated with O159 were in the range of 87.2-97.4%. In leek inoculated with low levels of O148, the sensitivities of sth, stp, and lt detection, direct plating, and the IMS-plating method were 59.0%, 33.3%, and 38.5%, respectively. Thus, ETEC in food contaminated with more than 21 CFU/25 g were detected at high rate (over 74%) using real-time PCR assays and IMS-plating onto selective agar. Therefore, screening sth, stp, and lt genes followed by isolation of STEC using the IMS-plating method may be an efficient method for ETEC detection.

Spatiotemporal treadmill gait measurements using a laser range scanner: feasibility study of the healthy young adults

OBJECTIVE

Spatio-temporal parameters are typically used for gait analysis. Although these parameters are measured by sophisticated systems such as 3D motion capture system or optoelectronic bars, these systems cannot be deployed easily because of their high costs, large space requirements and elaborate set-up. The purpose of this study is to develope a system for measuring spatiotemporal gait parameters using a laser range scanner during treadmill gait.

APPROACH

To calculate accurate spatiotemporal parameters, the differences between the laser range scanner measured values and the reference values obtained from a 3D motion capture system were investigated in thirty subjects. From measurements in time and position at foot contact/off, adjustments to compensate for the differences in time and position were derived. Then, to determine the validity of the proposed system, values from the proposed system and the reference system were compared in four additional subjects.

MAIN RESULTS

The results indicate that the data from the laser range scanner demonstrate certain differences in time and position compared with reference values. However, when compensation values were introduced, each spatiotemporal parameter correlated well with the reference values.

SIGNIFICANCE

This newer system is smaller, is easier to deploy and requires less training than the 3D motion capture system.

An interlaboratory study on efficient detection of Shiga toxin-producing Escherichia coli O26, O103, O111, O121, O145, and O157 in food using real-time PCR assay and chromogenic agar

To establish an efficient detection method for Shiga toxin (Stx)-producing Escherichia coli (STEC) O26, O103, O111, O121, O145, and O157 in food, an interlaboratory study using all the serogroups of detection targets was firstly conducted. We employed a series of tests including enrichment, real-time PCR assays, and concentration by immunomagnetic separation, followed by plating onto selective agar media (IMS-plating methods). This study was particularly focused on the efficiencies of real-time PCR assays in detecting stx and O-antigen genes of the six serogroups and of IMS-plating methods onto selective agar media including chromogenic agar. Ground beef and radish sprouts samples were inoculated with the six STEC serogroups either at 4-6CFU/25g (low levels) or at 22-29CFU/25g (high levels). The sensitivity of stx detection in ground beef at both levels of inoculation with all six STEC serogroups was 100%. The sensitivity of stx detection was also 100% in radish sprouts at high levels of inoculation with all six STEC serogroups, and 66.7%-91.7% at low levels of inoculation. The sensitivity of detection of O-antigen genes was 100% in both ground beef and radish sprouts at high inoculation levels, while at low inoculation levels, it was 95.8%-100% in ground beef and 66.7%-91.7% in radish sprouts. The sensitivity of detection with IMS-plating was either the same or lower than those of the real-time PCR assays targeting stx and O-antigen genes. The relationship between the results of IMS-plating methods and Ct values of real-time PCR assays were firstly analyzed in detail. Ct values in most samples that tested negative in the IMS-plating method were higher than the maximum Ct values in samples that tested positive in the IMS-plating method. This study indicates that all six STEC serogroups in food contaminated with more than 29CFU/25g were detected by real-time PCR assays targeting stx and O-antigen genes and IMS-plating onto selective agar media. Therefore, screening of stx and O-antigen genes followed by isolation of STECs by IMS-plating methods may be an efficient method to detect the six STEC serogroups.

[Molecular Detection Methods for Vibrio parahaemolyticus in Seafood]

To detect Vibrio parahaemolyticus in seafood, we evaluated efficient combinations of molecular methods with DNA extraction methods using heat extraction and alkaline heat extraction, and PCR, real-time PCR and loop-mediated isothermal amplification (LAMP) assays were performed targeting V parahaemolyticus species-specific genes (tlh and rpoD) and pathogenic factors genes (tdh and trh). The species-specific genes were detected in all combinations of two strains (a tdh * trh1-positive strain and a trh2-positive strain), two kinds of shellfish (oyster and bloody clams) and molecular methods with tlh-real time PCR or rpoD-LAMP assays with DNA of alkaline heat extraction at 85-145cfu/test level. tdh was detected in both seafoods with real time PCR assay with DNA of heat extraction at 85cfu/test level, and detected with the LAMP and real time PCR assays with DNA of alkaline heat extraction at 85cfu/test level. Detection of both trh1 and trh2 with the PCR assay with DNA of alkaline heat extraction was comparatively high though trh2 was detected with the LAMP assay with DNA of alkaline heat extraction at 145cfu/test level. It, however, is necessary to investigate more sensitive trh-detection methods. In this study, the results indicated that tlh-real time PCR or rpoD-LAMP, tdh-real time PCR and tdh-LAMP assays with DNA of alkaline heat extraction are relatively-sensitive methods to detect V. parahaemolyticus in seafood.

Comprehensive diagnostic ability of endocytoscopy compared with biopsy for colorectal neoplasms: a prospective randomized noninferiority trial

BACKGROUND AND STUDY AIMS

Endocytoscopy enables observation at 450-fold magnification during gastrointestinal endoscopy, allowing on-site "optical biopsy." We compared the accuracies of endocytoscopy and standard biopsy for the diagnosis of colorectal neoplasms.

PATIENTS AND METHODS

We performed a randomized, controlled, open-label trial of patients with colorectal lesions (≥ 5 mm) detected during colonoscopy in a tertiary referral center. We randomly assigned the 203 detected lesions of 170 eligible patients to either the endocytoscopy or standard biopsy group. An on-site endoscopist assessed the histopathology of the endocytoscopy group lesions according to the endocytoscopic findings, whereas a pathologist later assessed standard biopsy group lesions by microscopic examination of the biopsy specimens. We calculated the diagnostic accuracies in both groups with reference to the final histopathology of the resected specimens. The primary endpoint was to determine whether the diagnostic accuracy of endocytoscopy for neoplastic lesions was noninferior to that of standard biopsy (with a predefined noninferiority margin of 10%). Analyses were by intention-to-treat and per-protocol. The study is registered, number UMIN000003923.

RESULTS

Overall, 102 lesions in the endocytoscopy group and 101 in the standard biopsy group were available for primary outcome analysis. There were no complications. The diagnostic accuracy of endocytoscopy for the discrimination of neoplastic lesions was 94.1% (95% confidence interval 87.6% to 97.8%), whereas that of standard biopsy was 96.0% (90.2% to 98.9%), which is within the noninferiority margin (absolute difference -1.9%, -8.6% to +5.0%).

CONCLUSIONS

Endocytoscopy is noninferior to standard biopsy for the discrimination of neoplastic lesions. With its advantage of providing an on-site diagnosis, endocytoscopy could provide a novel alternative to standard biopsy in routine colonoscopy.

Characteristics of a sharp decrease in Vibrio parahaemolyticus infections and seafood contamination in Japan

Vibrio parahaemolyticus has been one of the most important foodborne pathogens in Japan since the 1960s, and a large epidemic was caused by the pandemic serotype O3:K6 from 1997 to 2001. V. parahaemolyticus infections, however, have sharply declined since that time. Data on serotypes isolated from 977 outbreaks were collected and analysed. Total and pathogenic, thermostable direct hemolysin (TDH) gene-positive V. parahaemolyticus were qualitatively and quantitatively detected in 842 seafood samples from wholesale markets in 2007-2009. Strains isolated from patients and seafood were analysed by serotyping, tdh-PCR, group-specific PCR for pandemic strains, and pulsed-field gel electrophoresis (PFGE). The sharp decrease in the infections from 1999 onwards was noted not only for O3:K6 infections but also for other serotypes. The change in the seafood contamination situation from 2001 to 2007-2009 was characterised by a decrease to three-fourths in the frequency of tdh-positive samples, although that decrease was small compared to the 18-fold decrease in the cases of V. parahaemolyticus outbreaks. PFGE detected the pandemic O3:K6 serotype in the same profile in seafood and patients from 1998 to the present. Because of no large decrease in seafood contamination by V. parahaemolyticus from the production to distribution stages and the presence of pandemic O3:K6 serotype in seafood to the present, it was suggested that the change of seafood contamination was unrelated to the sharp decrease in V. parahaemolyticus infections. V. parahaemolyticus infections might be prevented at the stages after the distribution stage.

Inducers and co-inducers of molecular chaperones

Molecular chaperones, which are mostly heat- or stress-induced proteins (HSPs), not only regulate various cellular functions such as protein folding, refolding of partially denatured proteins, protein transport across membranes, cytoskeletal organization, degradation of disabled proteins, and apoptosis, but also act as cytoprotective factors against deleterious environmental stresses. Recent studies indicated that moderate overexpression of molecular chaperones could confer cells and tissues stress tolerance and provide beneficial effects on various pathological states associated with protein misfolding and protein aggregation. Mild heat shock, transfection of HSP genes, and some chemical compounds are the major means of overexpression of molecular chaperones. In this review, we summarize recent studies of chemical compounds that could induce or enhance the expression of molecular chaperones or HSPs.

[Detection methods of enterohemorrhagic Escherichia coli O111 in beef: a collaborative study]

To establish a detection method for enterohemorrhagic Escherichia coli (EHEC) O111 in meat, a single-laboratory evaluation and a collaborative study were conducted focusing on comparisons of the efficiencies in combination with enrichment, a direct plating method and a plating method with immunomagnetic separation (IMS-plating method) using various agar media for EHEC O111, loop-mediated isothermal amplification (LAMP) assay targeting the Verocytotoxin (VT) gene as a molecular detection method. On a single-laboratory evaluation, enrichment in modified EC at 36 degrees C was inferior to that in modified EC supplemented with novobiocin (NmEC) and mEC at 42 degrees C to isolate EHEC O111 by plating methods. On a collaborative study, there were no significant differences between combinations of enrichment in NmEC at 42 degrees C-LAMP assay and enrichment in mEC at 42 degrees C-LAMP assay. The combinations of enrichment in NmEC at 42 degrees C-direct plating and enrichment in NmEC at 42 degrees C-IMS-plating were superior to combinations of enrichment in mEC at 42 degrees C-direct plating and enrichment in mEC at 42 degrees C-IMS-plating (p<0.05). There were no significant differences among the six different agar media by the direct plating and IMS-plating methods. As a result, it was suggested that the following methods are adequate for detection of EHEC O111 in beef: combinations of enrichment in NmEC at 42 degrees C, and direct plating and IMS-plating methods, or LAMP assay as a screening assay to detect VT gene followed by direct plating and IMS-plating methods.

Comparison of detection methods for Escherichia coli O157 in beef livers and carcasses

Beef organ meat, such as liver, and beef are major food sources contaminated with Escherichia coli O157. This study investigated the detection method of E. coli O157 in beef liver and carcass. In an experiment with beef liver inoculated with E. coli O157, the direct plating method, plating after the immunomagnetic separation (IMS) method, and Shiga toxin (Stx)-producing E. coli detection and E. coli O157 detection loop-mediated isothermal amplification (LAMP) assays were compared for the detection of Stx-producing E. coli O157. Fifty percent and 45% of samples were positive by Stx-producing E. coli detection LAMP assay and E. coli O157 detection LAMP assay, respectively. Thirty-five percent and 10% of samples were positive by the IMS method and direct plating method, respectively. In an examination of beef swab samples, contamination frequencies with E. coli O157 were analyzed by LAMP assays and the IMS method. E. coli O157 was detected in 12 of 230 samples (5.2%). There was no sample positive for E. coli O157 isolation but negative for LAMP assays for Stx gene and O157 antigen gene. Four samples (1.7%) were positive by both LAMP assays but negative by the IMS method. The result that there was no sample positive for the O157 antigen gene, but not the Stx gene, indicated that the IMS method failed to detect E. coli O157. Twenty-nine samples (12.6%) were positive for the Stx gene but not the O157 antigen gene. The results indicated that screening of Stx gene and O157 antigen gene by LAMP assays is effective in saving time and effort to isolate E. coli O157 by the IMS method because the LAMP assay is more sensitive. This suggested that samples positive for Stx gene and O157 antigen gene should be examined by the IMS method to isolate E. coli O157.

Feasibility of stomach exploration with a guided capsule endoscope

BACKGROUND AND STUDY AIMS

Video capsule endoscopy has been established in diagnosis of small-bowel disease and has been evaluated for esophageal pathology and recently for colorectal diagnostics. Gastric capsule endoscopy has not hitherto been feasible due to the stomach's large surface area and volume. We present the first application of a magnetically navigated capsule in the human stomach.

PATIENTS AND METHODS

29 volunteers and 24 patients (men 42, women 11; mean age 47.5 years) were included in a feasibility study. Low-level magnetic fields were used to maneuver the double-sensor video capsule within the human stomach with an air-water interface provided by ingestion of 1300 ml water within 1 hour before examination. Visualization of all parts of the stomach was attempted; time for visualization was recorded, and a subjective assessment of completeness of visualization was documented.

RESULTS

There was technical failure in one individual; thus technical success rate was 98 %. In the 52 remaining cases, examiners assessed that the antrum, body, fundus, and cardia were fully visualized in 98 %, 96 %, 73 % and 75 %, respectively. Mean duration of examinations was 30 minutes (range 8 - 50), with a longer time (mean 37 minutes) for volunteers for study reasons. In total, 30 findings were identified: 14 were detected by both gastroscopy and capsule, 10 lesions were identified by guided capsule examination only, 6 by gastroscopy only. No significant capsule-related adverse events occurred.

CONCLUSION

Magnetically navigated video capsule endoscopy appears to be feasible and sufficiently accurate for gastric examination. It may permit endoscopic examinations that are more patient-friendly and without sedation. Comparative studies are under way.

Salmonella prevalence in seafood imported into Japan

A total of 353 samples of 29 types of seafood were tested for Salmonella prevalence and total microbial population. Salmonella enterica serotype Weltevreden was isolated from 2 of 47 black tiger prawn samples. The contamination levels of Salmonella were in a range of <30 to 40 most probable number per 100 g. In addition, one sample of black tiger prawns and two samples of white shrimp were positive for Salmonella invA gene on PCR assay. Although the mean aerobic bacterial count was greater than 4 log CFU/g in most of the sample types, those in the two Salmonella-isolated samples of black tiger prawn were 7.48 and 5.18 log CFU/g, respectively. These results indicate the possibility that shrimp and prawns contribute to foodborne infections. The improvement of seafood quality is an important issue, and the information on contamination by pathogens should be provided as feedback to the originating country, with the aim of increasing safety.

Detection of Verotoxigenic Escherichia coli O157 and O26 in food by plating methods and LAMP method: a collaborative study

In order to establish a rapid and sensitive method for the detection of Verotoxigenic Escherichia coli O157 and O26, a collaborative study was conducted focusing on a comparison of the efficiency of loop-mediated amplification (LAMP) assay targeting the Verocytotoxin (also called Shiga toxin) gene, utilizing a direct plating method and a plating method with immunomagnetic separation (IMS-plating method) using various agar media. In combination with enrichment with the modified EC supplemented with novobiocin, E. coli O157 was detected in most samples of ground beef and alfalfa sprouts by LAMP assay, the direct plating method and the IMS-plating method. E. coli O26 was detected in approximately 100% of the food samples by LAMP assay. However, the IMS-plating and direct plating methods recovered 80 and 50% in ground beef samples, respectively. As a result, it was demonstrated the LAMP assay is superior to the IMS-plating method. Based on these results, it appears LAMP assay is effective as a screening assay to detect E. coli O157 and O26 from positive samples.

Sensitive and rapid detection of Vero toxin-producing Escherichia coli using loop-mediated isothermal amplification

A loop-mediated isothermal amplification (LAMP) assay was developed to detect Vero toxin (VT)-producing Escherichia coli rapidly (within 60 min). The 24 strains of VT-producing E. coli were successfully amplified, but 6 strains of non-VT-producing E. coli and 46 bacterial species other than E. coli were not. The sensitivity of the LAMP assay was found to be >0.7 c.f.u. per test using serogroups O157, O26 and O111 of VT-producing E. coli; this sensitivity is greater than that obtained by PCR assay. Furthermore, the LAMP assay was examined for its ability to detect VT-producing E. coli in food because of the difficulty of detection in food samples. The recovery of VT-producing E. coli by LAMP assay from beef and radish sprouts inoculated with the pathogen was high, similar to that obtained using culture methods with direct plating and/or plating after immunomagnetic separation. Although PCR assay was unable to recover VT-producing E. coli from half of the radish samples, LAMP assay was successful in most samples. In addition, VT-producing E. coli was successfully detected in cultures of the beef samples by LAMP assay, but not by the culture method. The LAMP products in naturally contaminated beef samples were analysed to confirm the specific amplification of the VT-encoding gene, and were found to show a specific ladder band pattern on agarose gel after electrophoresis. Additionally the sequences of the LAMP products coincided well with the expected sequences of the VT-encoding gene. These results indicate that the proposed LAMP assay is a rapid, specific and sensitive method of detecting the VT-producing E. coli.

Prediction of gait outcome with the knee-ankle-foot orthosis with medial hip joint in patients with spinal cord injuries: a study using recursive partitioning analysis

STUDY DESIGN

Retrospective study of the degree of gait independence achieved by persons with spinal cord injury (SCI) using knee-ankle-foot orthosis with a medial single hip joint (MSH-KAFO).

OBJECTIVE

To examine the effects of the neurological level, degree of paresis, age, and inhibitory physical/other factors on the gait with a MSH-KAFO in patients with SCIs.

SETTING

Three university hospitals and two rehabilitation hospitals in Japan.

METHODS

The 45 patients (36 men, nine women) examined included 10 with injuries in the cervical cord between C6 and C8 (group C), 20 with injuries in the upper-middle thoracic cord between T4 and T10 (group UT), and 15 with injuries in the lower thoracic-lumbar cord between T12 and L1 (group TL). Mean age was 34.0 years (range 16-68 years). Of these patients, 13 used the Walkabout, four used the gear joint, and 28 used the Primewalk as the medial hip joint. Recursive partitioning, which predicted the final status of gait from the level, degree of paresis, age, and inhibitory factors, was performed, and a decision tree for gait was constructed. Inhibitory factors were spasticity, involuntary spasms or muscle contractions, pain, contracture, weakness of the upper extremities, and decreased motivation to perform gait exercise. The degree of gait independence was rated on the following five-point scale: outdoor independent gait (5 points), indoor independent gait (4 points), indoor supervised gait (3 points), indoor assisted gait (2 points), and gait within parallel bars (1 point). New branches were added to the decision tree for gait based on the clinical experience, thereby constructing a new decision tree.

RESULTS

The coincident ratio between the value predicted on the basis of the decision tree of gait and the value actually observed was 53.3%. The coincident ratio between the value predicted on the basis of the modified decision tree of gait and the actually observed value was 68.9%.

CONCLUSION

The results provide valuable information to medical teams that may assist prescription of gait orthoses.

Detection of Salmonella enterica in naturally contaminated liquid eggs by loop-mediated isothermal amplification, and characterization of Salmonella isolates

Loop-mediated isothermal amplification (LAMP) assay was effective in detecting Salmonella enterica in naturally contaminated liquid egg samples. Salmonella was detected in 110 samples taken from four egg-breaking plants. The egg samples were pre-enriched in buffered peptone water (BPW) at 37 degrees C for 20 h. The selective enrichment was done in Rappaport-Vassiliadis or tetrathionate broth and plated onto xylose lysine deoxycholate agar and brilliant green agar, modified. In addition, the PCR assay was used to detect Salmonella after pre-enrichment in BPW at 37 degrees C for 20 h. The culture method and PCR assay were compared to the LAMP assay, which was also performed after pre-enrichment in BPW. PCR failed to detect Salmonella in 10% of 110 samples, whereas the culture method and LAMP assay successfully identified Salmonella in all samples. However, the LAMP assay was found to be much more rapid than the culture method and as sensitive in detecting Salmonella from liquid eggs. In all of the egg-breaking plants studied, Salmonella was isolated on most tested days. The positive samples showed that more than 75% of the Salmonella strains had identical genetic patterns when analyzed by pulsed-field gel electrophoresis. This suggests that the same Salmonella strains having survived long periods of time in the plants were contaminating the production line. The LAMP assay is rapid, specific, and sensitive for Salmonella detection in liquid eggs and is able to monitor Salmonella contamination in egg-handling plants more reliably.

Vertical-torsional oscillations and dissociated bilateral horizontal gaze palsy in a patient with a pontine cavernous angioma

We report the case of a 16 year old girl with vertical-torsional oscillations. She had a 4 year history of bilateral horizontal gaze palsy caused by a cavernous angioma in the medial part of the dorsal pons. She presented with vertical oscillopsia that had worsened during the past 3 months. Unilateral three dimensional eye movements and bilateral horizontal eye movements were recorded using a magnetic search coil method and direct current electro-oculography, respectively. She had vertical-torsional oscillations (average frequency: 3.0 Hz) leaving vertical saccades and pursuits intact. The average amplitudes of the vertical and torsional components were 2.0 degrees and 0.6 degrees , respectively. Her horizontal rapid eye movements were severely impaired; however, her horizontal pursuits and slow phases of vestibulo-ocular reflex were only partially impaired (gain<0.3, oculomotor range<+/-9 degrees ). Convergence and divergence were intact. Lesions involving the medial part of the dorsal pons and bilateral paramedian pontine reticular formation can induce vertical and torsional oscillations without disruption of vertical rapid eye movements.

Aqueous levels of macrophage migration inhibitory factor and monocyte chemotactic protein-1 in patients with diabetic retinopathy

AIMS

To investigate the relationship of aqueous macrophage migration inhibitory factor (MIF) and monocyte chemotactic protein-1 (MCP-1) levels with the clinical stage of diabetic retinopathy.

METHODS

We assayed MIF and MCP-1 levels in aqueous humour samples obtained from 40 diabetic patients (49 eyes) and 24 non-diabetic patients (31 eyes) using enzyme-linked immunosorbent assay. According to the clinical stage of diabetic retinopathy, the diabetic patients were classified into non-diabetic retinopathy (11 eyes), non-proliferative diabetic retinopathy (14 eyes) and proliferative diabetic retinopathy (24 eyes).

RESULTS

The aqueous levels of MIF (mean +/- sd) were 6.34 +/- 4.53 ng/ml in proliferative diabetic retinopathy, 3.22 +/- 1.71 ng/ml in non proliferative diabetic retinopathy, 1.25 +/- 0.96 ng/ml in non-diabetic retinopathy and 1.07 +/- 0.94 ng/ml in non-diabetic patients. Significant differences were found among these four groups (P < 0.0001). Aqueous MCP-1 levels were 1668.6 +/- 1442.3 pg/ml in proliferative diabetic retinopathy, 1528.6 +/- 1994.6 pg/ml in non-proliferative diabetic retinopathy, 690.2 +/- 402.1 pg/ml in non-diabetic retinopathy and 622.7 +/- 245.3 pg/ml in non-diabetic patients. Significant differences were also found among these four groups (P < 0.0001). After correcting for total aqueous protein, the ratios of MIF and MCP-1 to total protein remained significantly correlated with the clinical stage of diabetic retinopathy (P < 0.0001, P = 0.0004, respectively). The ratios of MIF to total protein significantly correlated with the ratios of MCP-1 to total protein in diabetic patients (r = 0.680, P < 0.0001).

CONCLUSIONS

Aqueous MIF levels significantly correlated with aqueous MCP-1 levels and the clinical stage of diabetic retinopathy. The results suggest that MIF has a co-operative role with MCP-1 in the progression of diabetic retinopathy.

Autoimmunity to Heat Shock Protein 40 in Ulcerative Colitis

Autoantibodies against heat shock protein 40 (HSP40) and their clinical significance in ulcerative colitis (UC) have not been evaluated before. Twenty-six tissue specimens of inflamed areas from patients with UC, 16 from patients with Crohn's disease (CD) and 16 endoscopically normal tissues were analysed for HSP40 expression. Sera from 47 patients with UC and 44 healthy volunteers were examined for the presence of autoantibodies against HSP40 by enzyme-linked immunosorbent assay test. Immunohistochemistry showed that 17 out of 26 specimens from UC patients, one specimen from a CD patient and one normal tissue specimen were positive for HSP40. Most HSP40-positive cells expressed CD68. Higher titres of anti-HSP40 autoantibodies were detected in sera from UC patients compared with healthy volunteers. In patients with inactive disease, those with proctitis or left-sided colitis had higher titres of anti-HSP40 autoantibodies than those with total colitis. Our study suggests that autoimmunity against HSP40 may have a beneficial effect in UC patients by limiting the extent of the disease.

Gambling activities of young Australians: developing a model of behaviour

As more gambling venues open in Australia, youth gambling as problem behaviour has been identified. The aim of this study was to assess youth gambling in a population with easy access to gambling, and to evaluate the adequacy of a model for predicting adolescent gambling frequency and problem gambling. The model comprised a combination of the Theory of Reasoned Action (TRA) (Ajzen & Fishbein, 1980), personality variables (venturesomeness, impulsiveness), and cognitive bias variables derived from Weinstein's (1980) propositions concerning unrealistic optimism about future life events. A sample of 1017 school- and university-based adolescents indicated relatively low frequencies of gambling and low scores on the problem gambling scale, with males scoring higher than females on both measures. The TRA was supported with about 30% of the variance of each of gambling behaviour and problem gambling accounted for by intentions, attitudes, and subjective norms. Personality factors added significantly to the prediction of gambling. The cognitive bias variables, although independently not statistically significant, further contributed to prediction.

NF-kappaB in epiretinal membranes after human diabetic retinopathy

AIMS/HYPOTHESIS

Formation of epiretinal membranes (ERMs) in the posterior fundus results in progressive deterioration of vision. ERMs have been associated with numerous clinical conditions including proliferative diabetic retinopathy (PDR), but its pathogenic mechanisms are still unknown. This study was conducted to examine whether or not nuclear factor kappa B (NF-kappaB), a transcription factor that can be activated by various pathological conditions, is involved in the formation of ERMs after PDR.

METHODS

ERM samples were obtained by vitrectomy from 22 cases with PDR aged 56+/-11 years with 18+/-10 years of diabetes and 15 cases with idiopathic ERM. They were processed for reverse transcription-polymerase chain reaction (RT-PCR) analysis. In addition, 5 ERM samples from PDR patients aged 51+/-16 years with 15+/-6 years of diabetes were processed for immunohistochemical analysis.

RESULTS

NF-kappaB mRNA expression levels were higher (20 out of 22 cases vs. 9 out of 15 subjects in idiopathic ERM, p<0.05) in PDR subjects. Immunohistochemical analysis showed NF-kappaB protein expression in all the 5 ERMs derived from PDR patients, and that region was partially double-labelled with interleukin-8 (IL-8) and von Willebrand factor (vWF).

CONCLUSIONS/INTERPRETATION

These results suggest a possibility that NF-kappaB is involved in the formation of ERMs after PDR, especially for the development of vascular endothelial cell component.

Newly developed 3D endoscopic system: preliminary experience

Although there have been earlier reports on the use of three-dimensional endoscopic systems in the gastrointestinal tract, real-time three-dimensional imaging has not previously been described. This paper presents experience in three cases with a novel endoscopic system for three-dimensional observation in clinical situations. Case 1 was a hyperplastic gastric polyp, the shape of which was considerably enhanced in comparison with two-dimensional endoscopic viewing. Case 2 was an advanced esophageal cancer, in which the sense of depth was improved in the esophagus. Case 3 was a depressed early gastric cancer, the shape of which was also enhanced. Between July 2001 and March 2002, three experienced endoscopists also used this new system in a further 34 patients. A three-dimensional endoscopic environment was visible with the system in all patients, and all of the endoscopists were able to obtain visual information regarding spatial depth. This experience suggests that the three-dimensional video-endoscopic system used here can be of value in gastrointestinal endoscopy.