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Proposal of a novel selective enrichment broth, NCT-mTSB, for isolation of Escherichia albertii from poultry samples. J Appl Microbiol 2021; 132:2121-2130. [PMID: 34735750 DOI: 10.1111/jam.15353] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/05/2021] [Accepted: 10/29/2021] [Indexed: 11/27/2022]
Abstract
AIMS Escherichia albertii is an emerging diarrheagenic pathogen causing food- and water-borne infection in humans. However, no selective enrichment broths for E. albertii have ever been reported. In this study, we tested several basal media, selective supplements and culture conditions which enabled selective enrichment of E. albertii. METHODS AND RESULTS We developed a selective enrichment broth, novobiocin-cefixime-tellurite supplemented modified tryptic soy broth (NCT-mTSB). NCT-mTSB supported the growth of 22 E. albertii strains, while inhibited growth of other Enterobacteriaceae at 37°C, except for Escherichia coli and Shigella spp. Enrichment of E. albertii was improved further by growth at 44°C, a temperature that suppresses growth of several strains of E. coli/Shigella. Combined use of NCT-mTSB with XR-DH-agar, xylose-rhamnose supplemented deoxycholate hydrogen sulphide agar, enabled isolation of E. albertii when at least 1 CFU of the bacterium was present per gram of chicken meat. This level of enrichment was superior to those obtained using buffered peptone water, modified-EC broth, or mTSB (with novobiocin). CONCLUSIONS Novobiocin-cefixime-tellurite supplemented modified tryptic soy broth enabled effective enrichment of E. albertii from poultry samples and was helpful for isolation of this bacterium. SIGNIFICANCE AND IMPACT OF STUDY To our knowledge, this is the first report of selective enrichment of E. albertii from poultry samples.
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Prevalence and Antimicrobial Susceptibility of Bacterial Pathogens in Ready-to-Eat Foods Retailed in Osaka Prefecture, Japan. J Food Prot 2018; 81:1450-1458. [PMID: 30080122 DOI: 10.4315/0362-028x.jfp-18-035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The potential human health risk of Japanese ready-to-eat (RTE) foods was investigated by determining the contamination by foodborne bacterial pathogens, the prevalence of opportunistic and nosocomial pathogens, and the antibiotic susceptibility of the isolates recovered from 96 samples of lightly pickled vegetables, 88 samples of Western-style desserts, and 98 samples of RTE fish and seafood products sold at retail in Osaka, Japan. Staphylococcus aureus, including isolates producing staphylococcal enterotoxin (SE), were isolated from six lightly pickled vegetable products, seven Western-style dessert products, and three RTE fish and seafood products. Of these isolates, one SEC-producing isolate from a cake was identified as community-acquired methicillin-resistant S. aureus, which was multilocus sequence type 8 and staphylococcal cassette chromosome mec type IV. Enterobacteriaceae species, including Escherichia coli, Klebsiella oxytoca, Klebsiella pneumoniae, Proteus mirabilis, Serratia marcescens, Citrobacter freundii-Citrobacter braakii, and/or the Enterobacter cloacae complex, were isolated from 92 (95.8%) of the lightly pickled vegetable products, 39 (44.3%) of the Western-style dessert products, and 74 (75.5%) of the RTE fish and seafood products. On the basis of the antimicrobial susceptibility profiles of the opportunistic and nosocomial Enterobacteriaceae pathogens, the third-generation cephalosporin, fosfomycin, and quinolone resistance determinants were investigated. We detected AmpC products of the CIT group and a qnrB9 product in 5 and 1 C. freundii-C. braakii isolates, respectively, and fosA gene products in 15 E. cloacae complex isolates. Because RTE foods are consumed without a heating process, the spread of bacterial pathogens from contaminated food to human consumers is possible. RTE foods must be handled using hygienic procedures from the processing steps to the table to reduce the prevalence of potentially pathogenic or pathogenic bacteria and to prevent bacterial growth.
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Comparison of listeriolysin O and phospholipases PlcA and PlcB activities, and initial intracellular growth capability among food and clinical strains of Listeria monocytogenes. J Appl Microbiol 2018; 124:899-909. [PMID: 29322608 DOI: 10.1111/jam.13692] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/21/2017] [Accepted: 01/04/2018] [Indexed: 11/29/2022]
Abstract
AIMS We investigated whether Listeria monocytogenes strains differ in their ability to escape from the primary phagosome after internalization into human intestinal epithelial cells. METHODS AND RESULTS Food and clinical strains were used to study specific alleles; the activities of listeriolysin O (LLO) and phospholipases PlcA and PlcB, which promote rupture of the phagocytic vacuole; and initial intracellular bacterial growth in Caco-2 cells. Results showed no difference in LLO activities between food and clinical strains or among serotypes. In contrast, the LLO truncation mutant lacked detectable haemolytic activity and intracellular growth. PlcA and PlcB produced by the strains of serotypes 4b/4e and 1/2b exhibited significantly lower activities than those of serotypes 1/2a and 1/2c. In contrast, the strains of serotype 1/2b grew significantly faster than those of serotypes 4b/4e and 1/2a. Moreover, the PrfA truncation mutants lacked LLO and phospholipases activities and did not show intracellular growth. CONCLUSIONS We determined that LLO and PrfA mutants exert a significant effect on intracellular growth, although it was unclear from this study whether PlcA and PlcB alleles affect escape from vacuoles. SIGNIFICANCE AND IMPACT OF THE STUDY This study estimates that low-virulence L. monocytogenes strains associated with escape ability from the primary vacuoles are not widely distributed among food strains.
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Prevalence of Listeria monocytogenes in Retail Lightly Pickled Vegetables and Its Successful Control at Processing Plants. J Food Prot 2017; 80:467-475. [PMID: 28207308 DOI: 10.4315/0362-028x.jfp-16-062] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Incidences of food poisoning traced to nonanimal food products have been increasingly reported. One of these was a recent large outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 infection from the consumption of lightly pickled vegetables, indicating the necessity of imposing hygienic controls during manufacturing. However, little is known about the bacterial contamination levels in these minimally processed vegetables. Here we examined the prevalence of STEC, Salmonella spp., and Listeria monocytogenes in 100 lightly pickled vegetable products manufactured at 55 processing factories. Simultaneously, we also performed quantitative measurements of representative indicator bacteria (total viable counts, coliform counts, and β-glucuronidase-producing E. coli counts). STEC and Salmonella spp. were not detected in any of the samples; L. monocytogenes was detected in 12 samples manufactured at five of the factories. Microbiological surveillance at two factories (two surveys at factory A and three surveys at factory B) between June 2014 and January 2015 determined that the areas predominantly contaminated with L. monocytogenes included the refrigerators and packaging rooms. Genotyping provided further evidence that the contaminants found in these areas were linked to those found in the final products. Taken together, we demonstrated the prevalence of L. monocytogenes in lightly pickled vegetables sold at the retail level. Microbiological surveillance at the manufacturing factories further clarified the sources of the contamination in the retail products. These data indicate the necessity of implementing adequate monitoring programs to minimize health risks attributable to the consumption of these minimally processed vegetables.
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Enterococcus saigonensis sp. nov., isolated from retail chicken meat and liver. Int J Syst Evol Microbiol 2016; 66:3779-3785. [DOI: 10.1099/ijsem.0.001264] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Development and application of a multiplex PCR assay for detection of the Clostridium perfringens enterotoxin-encoding genes cpe and becAB. J Microbiol Methods 2016; 127:172-175. [PMID: 27291714 DOI: 10.1016/j.mimet.2016.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/09/2016] [Accepted: 06/09/2016] [Indexed: 11/19/2022]
Abstract
Clostridium perfringens causes food-borne gastroenteritis following the consumption of contaminated food by producing C. perfringens enterotoxin (CPE) in the intestines. Recently, we reported a novel enterotoxin, binary enterotoxin of C. perfringens (BEC) in C. perfringens isolates, which caused two disease outbreaks in Japan. Consequently, in the event of food poisoning outbreaks caused by C. perfringens, it is now necessary to screen for both the cpe and becAB genes by diagnostic PCR. Here, we present a simple multiplex PCR method for simultaneous detection of cpe, becAB and a C. perfringens control locus, phospholipase C (plc). Applying this method, we investigated the prevalence of cpe- or becAB-carrying C. perfringens strains in human stool and bovine rectum swab samples. Using a total of 169 isolates, we found that the percentage of becAB-carrying strains was very small (0.59%), one-tenth that of cpe-carrying strains. The simple method presented in this study with high specificity and sensitivity to C. perfringens will be a useful tool to survey the global prevalence of becAB-carrying C. perfringens strains.
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Prevalence and Antimicrobial Susceptibility of Enterobacteriaceae Isolated from Retail Pepper in Vietnam. J Food Prot 2016; 80:716-724. [PMID: 28350183 DOI: 10.4315/0362-028x.jfp-16-501] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 01/06/2017] [Indexed: 11/11/2022]
Abstract
To investigate the microbial quality of retail pepper in Vietnam, the enumeration and detection of Enterobacteriaceae and the screening of cefotaxime (CTX)-resistant coliforms were performed by using 84 commercial samples. Although Enterobacteriaceae were isolated from 78 samples, the number of Enterobacteriaceae was lower than 1.0 log CFU/g in 46 samples. For the detection of Enterobacteriaceae with the International Organization for Standardization methods, Salmonella spp., Escherichia coli, Klebsiella pneumoniae, Cronobacter sakazakii, and Enterobacter cloacae complex were isolated from 5, 12, 36, 19, and 30 samples, respectively. During screening of CTX-resistant coliforms, K. pneumoniae, C. sakazakii, and E. cloacae complex were isolated from 8, 1, and 21 samples, respectively. Seven K. pneumoniae and seven E. cloacae complex isolates obtained in the screening of CTX-resistant coliforms were resistant to at least one of the three third-generation cephalosporins (CTX, ceftazidime, and cefpodoxime). Moreover, one E. cloacae complex cluster IV and all K. pneumoniae isolates were positive for extended-spectrum β-lactamase genes or plasmid-mediated AmpC β-lactamase genes or both. Additionally, two extended-spectrum β-lactamase-producing K. pneumoniae isolates and one AmpC β-lactamase-producing E. cloacae complex cluster IV isolate were positive for the plasmid-mediated quinolone resistance determinants and also had amino acid alterations in the quinolone resistance-determining regions of GyrA and ParC. Furthermore, 10 E. cloacae complex isolates were positive for the plasmid-mediated fosfomycin resistance gene fosA. As pepper is often consumed without a heating process, the possible spread to humans of foodborne, opportunistic, and nosocomial infection pathogens or resistance genes from foods prepared or seasoned with pepper cannot be excluded. Therefore, it is necessary to handle pepper by using hygienic conditions during the cultivation, harvesting and processing steps.
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Characterization of specific alleles in InlA and PrfA of Listeria monocytogenes isolated from foods in Osaka, Japan and their ability to invade Caco-2 cells. Int J Food Microbiol 2015; 211:18-22. [PMID: 26143289 DOI: 10.1016/j.ijfoodmicro.2015.06.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Revised: 06/23/2015] [Accepted: 06/26/2015] [Indexed: 10/23/2022]
Abstract
Listeria monocytogenes expresses the surface protein internalin A (InlA), enabling the invasion of human intestinal epithelial cells to cause severe food-borne diseases. Full-length sequence analysis of inlA of 114 food isolates resulted in the detection of 29 isolates with a premature stop codon (PMSC) mutation and 6 isolates with 3-codon deletion mutations (aa 738 to 740) in inlA. The isolates with inlA PMSCs demonstrated a significantly lower level of invasion than the other food isolates in a Caco-2 cell invasion assay (P<0.01), but the isolates with the 3-codon deletion exhibited invasion comparable to the isolates with non-truncated InlA (P>0.05). According to analysis of the positive regulatory factor A (PrfA) sequences of 114 L. monocytogenes isolates, 7 isolates of serotype 1/2a from chicken samples contained a PrfA protein with a 5-nucleotide deletion from 712 to 716, including a stop codon. Although the isolates with a 5-nucleotide deletion in prfA demonstrated invasion comparable to the isolates with non-truncated InlA and PrfA after growth at 30 °C (P>0.05), they exhibited a significantly higher level of invasion than the other isolates after growth at 20 °C (P<0.01). To the authors' knowledge, this is the first report of L. monocytogenes isolates with the stop-codon deletion of PrfA.
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A highly rapid and simple competitive enzyme-linked immunosorbent assay for monitoring paralytic shellfish poisoning toxins in shellfish. Food Chem 2014; 162:94-8. [DOI: 10.1016/j.foodchem.2014.04.038] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 02/06/2014] [Accepted: 04/09/2014] [Indexed: 11/16/2022]
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A foodborne outbreak of gastrointestinal illness caused by enterotoxigenic Escherichia coli serotype O169:H41 in Osaka, Japan. Jpn J Infect Dis 2014; 66:530-3. [PMID: 24270144 DOI: 10.7883/yoken.66.530] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We describe our laboratory investigation of a massive foodborne outbreak of gastrointestinal illness caused by enterotoxigenic Escherichia coli (ETEC) serotype O169:H41 that occurred during a 2-day traditional festival held in September 2012 in Osaka Prefecture, Japan. Of 126 customers who patronized a particular Japanese restaurant during the event, 102 developed symptoms of gastrointestinal disease. We isolated strains of ETEC serotype O169:H41 from 1 food sample and from fecal samples collected from 19 of 34 patients and 2 of 4 food handlers. Pulsed-field gel electrophoresis analysis of these isolates suggested that the foodborne pathogen that caused the diarrheal outbreak was a specific clone of ETEC serotype O169:H41. Based on these findings and our interviews with the restaurant owner and employees, we concluded that a likely cause of the outbreak was an overwhelmed capacity of the restaurant kitchen in terms of preservation of sanitary procedures during the festival and the inability of the restaurant staff to handle the relatively large quantity of food to ensure a lack of contamination with ETEC. Thus, we reconfirm that ETEC strains of serotype O169:H41 remain important causes of domestic foodborne outbreaks in developed countries, including Japan.
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Simultaneous Immunomagnetic Separation Method for the Detection of Escherichia coli O26, O111, and O157 from Food Samples. J Food Prot 2014; 77:15-22. [PMID: 24405994 DOI: 10.4315/0362-028x.jfp-13-225] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We performed a simultaneous immunomagnetic separation (IMS) assay on Shiga toxin-producing Escherichia coli (STEC) serogroups O26, O111, and O157 with immunobeads coated with O26, O111, or O157 antibodies that were simultaneously added to an aliquot of food culture. We also compared the usefulness of CHROMagar STEC medium against various selective isolation agars designed to test for the three serogroups. Samples of sliced beef, ground beef, and radish sprout were artificially contaminated with STEC O26, O111, and O157 strains after incubation in enrichment broth and were subjected to conventional and simultaneous IMS assays. Simultaneous IMS did not affect the sensitivity of target cell detection. For STEC O26, O111, and O157 inoculated into the enriched samples of sliced beef and radish sprout, the detection ability of CHROMagar STEC was similar to or exceeded that of other isolation agars. However for STEC O157 inoculated into ground beef cultures, cefixime tellurite sorbitol MacConkey agar (CT-SMAC) was the superior detection medium. The performance of simultaneous IMS combined with CT-SMAC and CHROMagar STEC detection is similar to that of the Japanese standard method for isolating E. coli O26, O111, and O157. However, the proposed approach involves the same time, materials, and labor costs as the standard E. coli O157 reference procedure but allows detection of three E. coli serotypes rather than a single strain.
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The HESI inter-laboratory miRNA project. Toxicol Lett 2013. [DOI: 10.1016/j.toxlet.2013.06.176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Multi-laboratory assessment of best practices for quantification of microRNAs associated with isoproterenol-induced myocardial injury in the urine and plasma of rats. Toxicol Lett 2013. [DOI: 10.1016/j.toxlet.2013.05.037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Production and characterization of a monoclonal antibody against recombinant thermolabile hemolysin and its application to screen for Vibrio parahaemolyticus contamination in raw seafood. Food Control 2012. [DOI: 10.1016/j.foodcont.2011.07.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Isolation and characterization of vanA genotype vancomycin-resistant Enterococcus cecorum from retail poultry in Japan. Int J Food Microbiol 2011; 153:372-7. [PMID: 22192623 DOI: 10.1016/j.ijfoodmicro.2011.11.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 11/15/2011] [Accepted: 11/27/2011] [Indexed: 11/18/2022]
Abstract
The isolation rate of high-level vancomycin-resistant enterococci (VRE) from poultry samples in Japan has increased in recent years. As this raises concerns for the potential spread of genes encoding vancomycin resistance, poultry is routinely screened for VRE. Here, we report the isolation and characterization of a vanA genotype vancomycin-resistant Enterococcus cecorum strain (E. cecorum IPHa84) from retail domestic poultry in September 2009. The species identification was performed by biochemical testing and sequencing of the 16S rRNA and manganese-dependent superoxide dismutase genes. The vancomycin and teicoplanin susceptibility tests showed that E. cecorum IPHa84 was resistant to vancomycin and susceptible to teicoplanin, demonstrating that this isolate was VanB phenotype-vanA genotype VRE. Moreover, a vanA gene cluster was found in a chromosomally encoded Tn1546-related element, which exhibited the characteristic structure of the prototype Tn1546 element, but contained eight point mutations. The vanS sequence of E. cecorum IPHa84 contained three point mutations and was 100% identical to those of VRE isolated from different broiler droppings in Japan prior to the banning of avoparcin, indicating that the Tn1546-related element may be stable in poultry production environments, even in the absence of selective pressure. The isolation of a novel enterococcal species harboring the vanA gene reconfirms that poultry can serve as a reservoir of VanA-type VRE or vancomycin resistance genes, and suggests that the transmission of these risk factors from poultry to humans through the food chain remains a potential threat in Japan.
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Molecular Epidemiological Investigation of a Diffuse Outbreak Caused bySalmonella entericaSerotype Montevideo Isolates in Osaka Prefecture, Japan. Foodborne Pathog Dis 2011; 8:1083-8. [DOI: 10.1089/fpd.2011.0862] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Comparison of four enrichment broths for the detection of non-O157 Shiga-toxin-producing Escherichia coli O91, O103, O111, O119, O121, O145 and O165 from pure culture and food samples. Lett Appl Microbiol 2011; 53:167-73. [DOI: 10.1111/j.1472-765x.2011.03085.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Application of a modified loop-mediated isothermal amplification kit for detecting Norovirus genogroups I and II. J Med Virol 2010; 81:2072-8. [PMID: 19856470 PMCID: PMC7166440 DOI: 10.1002/jmv.21626] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Norovirus is a major etiologic agent in worldwide outbreaks of gastroenteritis associated with food as well as person‐to‐person transmission. The ubiquitous nature of Norovirus necessitates simple and rapid detection methods with high accuracy and sensitivity. To this end, several investigators have evaluated the usefulness of commercial reverse‐transcription loop‐mediated isothermal amplification (RT‐LAMP) kits for detecting Norovirus genogroups I (GI) and II (GII). In previous studies, the conventional Loopamp kit for Norovirus GII showed a relatively high detection rate, while that for Norovirus GI showed a relatively low detection rate. In the present study, clinical Norovirus specimens were used to compare the detection rate of a modified Loopamp kit for Norovirus GI with the rates of the conventional Loopamp kit for Norovirus GI and an “in‐house” RT‐LAMP GI primer set, methods which had a high detection rate. Results from the present study showed that the modified Loopamp kit for Norovirus GI had a higher detection rate for two viral genotypes (GI.3, GI.11). On comparison with an “in‐house” GII primer set using genotype GII.4 viruses circulating recently, the detection rate by the Loopamp kit for Norovirus GII was found to be higher, with a 98% detection rate. These results indicate the applicability of the modified LAMP kit for GI and the conventional LAMP kit for GII for detection of Noroviruses in clinical samples. J. Med. Virol. 81:2072–2078, 2009. © 2009 Wiley‐Liss, Inc.
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Simultaneous enrichment of shiga toxin-producing Escherichia coli O157 and O26 and Salmonella in food samples using universal preenrichment broth. J Food Prot 2009; 72:2065-70. [PMID: 19833028 DOI: 10.4315/0362-028x-72.10.2065] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Universal preenrichment broth (UPB) was compared with modified Escherichia coli broth with novobiocin (mEC+n) for enrichment of Shiga toxin-producing E. coli O157 and O26, and with buffered peptone water (BPW) for preenrichment of Salmonella enterica. Ten strains each of the three pathogens were inoculated into beef and radish sprouts following thermal, freezing, or no treatment. With regard to O157 and O26, UPB incubated at 42 degrees C recovered significantly more cells from inoculated beef than UPB at 35 degrees C and from radish sprout samples than UPB at 35 degrees C and mEC+n. With regard to Salmonella, UPB incubated at 42 degrees C was as effective as UPB at 35 degrees C and BPW at recovering cells from beef and radish sprout samples. No significant difference was noted between the effectiveness of UPB at 42 degrees C and UPB at 35 degrees C or BPW in the recovery of Salmonella from 205 naturally contaminated poultry samples. By using UPB at 42 degrees C, one O157:H7 strain was isolated from the mixed offal of 53 beef samples, 6 cattle offal samples, and 50 pork samples all contaminated naturally, with no pathogen inoculation. The present study found that UPB incubated at 42 degrees C was as effective as, or better than, mEC+n for enrichment of O157 and O26 and comparable to BPW for preenrichment of Salmonella. These findings suggest that a great deal of labor, time, samples, and space may be saved if O157, O26, and Salmonella are enriched simultaneously with UPB at 42 degrees C.
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Evaluation and application of reverse transcription loop-mediated isothermal amplification for detection of noroviruses. J Med Virol 2007; 79:326-34. [PMID: 17245722 PMCID: PMC7166943 DOI: 10.1002/jmv.20802] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A one-step reverse transcription loop-mediated isothermal amplification (RT-LAMP) assay for the detection of norovirus (NV) was developed. In order to design primer sets for the detection of a wide range of NVs, NVs were categorized into three groups, that is, genogroup I (GI), prevalent GII, and minor GII; three sets of primers were developed for each group. Clinical specimens of patients suffering from enteric RNA viruses, such as NV, group A and C rotavirus, and sapovirus were examined using these primer sets. Various genotypes of NVs were detected in clinical specimens from patients infected with NV where no false positive reaction was observed with other enteric RNA viruses. Additionally, 88 samples of acute gastroenteritis outbreaks were analyzed by an RT-LAMP assay and compared with the results of routine RT-PCR. The results of the RT-LAMP assay corresponded well to that of RT-PCR. These findings suggest the practical application of the RT-LAMP assay for the detection of NVs in clinical specimens. Consequently, the RT-LAMP system and conventional detection kits (NVGI and NVGII detection kits; Eiken Chemical Co., Ltd., Japan) were compared. The detection rate of the prevalent and minor GII primer sets was similar to that of the conventional NVGII kit, while the detection rate of the GI primer set is different because it can detect several genotypes better than the conventional NVGI kit. This is an initial report that the RT-LAMP system is able to detect NVs in clinical specimens within a wide range.
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Histidine decarboxylases and their role in accumulation of histamine in tuna and dried saury. Appl Environ Microbiol 2007; 73:1467-73. [PMID: 17220267 PMCID: PMC1828783 DOI: 10.1128/aem.01907-06] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2006] [Accepted: 12/21/2006] [Indexed: 11/20/2022] Open
Abstract
Histamine-producing bacteria (HPB) such as Photobacterium phosphoreum and Raoultella planticola possess histidine decarboxylase (HDC), which converts histidine into histamine. Histamine fish poisoning (HFP) is attributable to the ingestion of fish containing high levels of histamine produced by HPB. Because freezing greatly decreases the histamine-producing ability of HPB, especially of P. phosphoreum, it has been speculated that HFP is caused by HDC itself from HPB cells autolyzing during frozen storage, even when HPB survive frozen storage. Here we constructed recombinant HDCs of P. phosphoreum, Photobacterium damselae, R. planticola, and Morganella morganii and investigated the ability of HDCs to produce sufficient histamine to cause HFP. To elucidate the character of these HDCs, we examined the specific activity of each recombinant HDC at various temperatures, pH levels, and NaCl concentrations. Further, we also investigated the stability of each HDC under different conditions (in reaction buffer, tuna, and dried saury) at various temperatures. P. damselae HDC readily produced sufficient histamine to cause HFP in fish samples. We consider that if HDC is implicated as an independent cause of HFP in frozen-thawed fish, the most likely causative agent is HDC of P. damselae.
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Norovirus outbreaks at nursing homes in osaka, Japan. Jpn J Infect Dis 2005; 58:254-5. [PMID: 16116265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
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A norovirus outbreak of gastroenteritis linked to packed lunches. Jpn J Infect Dis 2005; 58:253. [PMID: 16116264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
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Outbreak of food poisoning caused by lunch boxes prepared by a company contaminated with multidrug resistant Salmonella typhimurium DT104. Jpn J Infect Dis 2005; 58:55-6. [PMID: 15728997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
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Photobacterium phosphoreum caused a histamine fish poisoning incident. Int J Food Microbiol 2004; 92:79-87. [PMID: 15033270 DOI: 10.1016/j.ijfoodmicro.2003.08.019] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2002] [Revised: 06/18/2003] [Accepted: 08/07/2003] [Indexed: 11/29/2022]
Abstract
An incident of histamine fish poisoning (HFP) occurred due to the consumption of iwashi maruboshi (dried sardine) in Osaka, Japan in March 2002. A histamine-producing bacterial strain, YS4-7, was isolated from iwashi maruboshi that contained 1700 mg of histamine per kilogram. This strain was identified as Photobacterium phosphoreum by biochemical examinations and partial sequencing of 16S rDNA. P. phosphoreum YS4-7 showed greater capability as a histamine producer at 4 and 12 degrees C than Morganella morganii JCM 1672. Strain YS4-7 produced 546 mg of histamine per kilogram in a sardine homogenate stored for 12 h at 20 degrees C. M. morganii, Raoultella planticola and Hafnia alvei have been isolated from fish implicated in HFP incidents, whereas this is the first report of P. phosphoreum being the causative bacterium in a sporadic case of histamine food poisoning.
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Klebsiella pneumoniae produces no histamine: Raoultella planticola and Raoultella ornithinolytica strains are histamine producers. Appl Environ Microbiol 2002; 68:3462-6. [PMID: 12089029 PMCID: PMC126807 DOI: 10.1128/aem.68.7.3462-3466.2002] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2001] [Accepted: 04/11/2002] [Indexed: 11/20/2022] Open
Abstract
Histamine fish poisoning is caused by histamine-producing bacteria (HPB). Klebsiella pneumoniae and Klebsiella oxytoca are the best-known HPB in fish. However, 22 strains of HPB from fish first identified as K. pneumoniae or K. oxytoca by commercialized systems were later correctly identified as Raoultella planticola (formerly Klebsiella planticola) by additional tests. Similarly, five strains of Raoultella ornithinolytica (formerly Klebsiella ornithinolytica) were isolated from fish as new HPB. R. planticola and R. ornithinolytica strains were equal in their histamine-producing capabilities and were determined to possess the hdc genes, encoding histidine decarboxylase. On the other hand, a collection of 61 strains of K. pneumoniae and 18 strains of K. oxytoca produced no histamine.
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Association of p53 gene mutation and telomerase activity in resectable non-small cell lung cancer. Chest 2001; 120:589-94. [PMID: 11502663 DOI: 10.1378/chest.120.2.589] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
PURPOSE Mutation of the p53 gene and deregulation of telomerase may be essential for canceration in some malignant diseases. However, relationships between these occurrences have not yet been clarified. We examined the roles of p53 gene mutation and telomerase activity relative to the clinical and pathologic features of non-small cell lung carcinoma (NSCLC). METHODS Frozen sections of 40 surgically resected NSCLC specimens were used. DNA extracted from fresh tumor specimens was analyzed with polymerase chain reaction (PCR), single-strand conformation polymorphism (SSCP) method, to screen alterations in the p53 gene. Exons showing aberrant band shifts on SSCP were reamplified, and the PCR products were directly sequenced. In addition, the telomerase activity of the same specimens was analyzed quantitatively with the fluorescence-based telomeric repeat amplification protocol assay, and the total product generated (TPG) method. Clinical and pathologic parameters were evaluated using a statistical analysis system. RESULTS Mutations of the p53 gene relevant to an altered protein were confirmed in 19 of 40 specimens (47.5%). The TPG of 40 specimens was 75.24 +/- 15.55 (mean +/- SE). The TPG of the 19 specimens positive for p53 gene mutation was significantly higher than that of the 21 specimens negative for p53 gene mutation. Furthermore, the degree of cell differentiation was significantly correlated with both p53 gene mutation and high telomerase activity. CONCLUSIONS p53 gene mutation and high telomerase activity cooperate to induce tumorigenesis and low-grade differentiation in NSCLC. Simultaneous occurrence of p53 gene mutation and high telomerase activity may be relevant to the grade of malignancy in NSCLC.
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Abstract
PURPOSE In this study, we investigated factors that determined prognosis in patients who underwent surgery for metastatic lung tumors, focusing on early relapse of metastatic lung lesions after surgery, and considered countermeasures for improving long-term results based on this study. PATIENTS This study was performed in patients with metastatic lung tumors who underwent surgery during the 22 years after November 1975 in this department. RESULTS The 1-year, 3-year, and 5-year survival rates in all patients were 70%, 42%, and 37%, respectively. On comparison among the groups, there were no significant differences by gender, age, organ with the primary lesion, disease-free interval, number of metastases, or surgical procedure. However, prognosis was significantly poorer in patients with recurrent metastatic lung lesions. Prognosis was especially poor in patients with recurrence within 6 months after pneumonectomy, and this was an important factor that worsened the surgical results. CONCLUSIONS As the mechanism of early recurrence of lung metastasis after surgery for metastatic lung tumor, multiple micrometastases (dormancy) that cannot be detected during surgery for metastatic lung tumor may be present in the lung. Establishment of a method of controlling an increase in dormant metastasis may lead to improvement of surgical results of metastatic lung tumors.
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An availability of video-assisted thoracic surgery for the resection of pulmonary metastases. Ann Thorac Cardiovasc Surg 1999; 5:69-73. [PMID: 10332108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Abstract
We report the use of video-assisted thoracic surgery (VATS) as a treatment for pulmonary metastases. Eight patients with metastatic lung cancer were treated with VATS techniques. These patients included 5 males and 3 females whose ages ranged from 34 to 61 years (average: 47.4). Their primary diseases were seminoma (n = 3), renal cell carcinoma (n = 2), colon carcinoma (n = 1), mammary carcinoma (n = 1) and choriocarcinoma (n = 1). Computed tomography (CT) scans with current generation scanners were performed preoperatively and revealed one metastatic lesion in each of five cases and two lesions in each of the other three cases. In one case, one lesion was located in each of the lungs. Tumor size ranged from 5 to 30 mm in diameter, and all lesions were in the peripheral field of the lung. VATS was carried out with three surgical ports for three cases, two surgical ports for one case, and only one port for two cases. For all cases, an endo-stapler was utilized. In two cases, the preoperative point-marking technique for tumors was employed under the guidance of CT imaging. All patients were discharged from the hospital with no complications, and were followed up with no evidence of lung recurrence. Our criteria in selecting patients for the VATS removal of metastatic lung tumors are as follows: 1) tumors are less than 30 mm in diameter in the peripheral lung, 2) the number of tumors detected by CT scan, etc., is one or two. We conclude that VATS is a good candidate for the resection of lung metastases in the selected cases. Long term outcome remains to be solved in the future.
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The prognostic factor of the surgically treated metastatic lung cancer. THE KOBE JOURNAL OF MEDICAL SCIENCES 1998; 44:247-64. [PMID: 10401227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Surgical treatment for metastatic lung tumor has also been aggressively performed to treat multiple or bilateral lesions recently. However, in some patients, metastatic pulmonary foci have recurred after surgery for metastatic lung tumor. These foci could not be controlled even after performing thoracotomy several times in some patients. In this study, we examined prognostic factors in patients undergoing surgery for metastatic lung tumor with respect to early relapse of metastatic pulmonary foci after surgery, and discussed strategies for improving long-term results. This study included 120 patients who underwent surgery for metastatic lung tumor in our department between November 1975 and November 1997. Overall, the 5-year survival rate was 37.1%. When results were compared among groups, there were no significant differences related to age, gender, primary organ, DFI, number of metastatic foci or surgical technique. However, the prognosis was significantly poorer in patients with recurrent metastatic pulmonary foci after surgery. Especially in patients with early relapse within 6 months after resection of the lung, the prognosis was markedly poor. Early relapse was an important factor involved in unfavorable surgical outcomes. The mechanism involved in the early relapse of metastatic pulmonary foci after surgery for metastatic lung tumor may be associated with the presence of several micrometastases that could not be recognized during surgery for metastatic lung tumor, that is, dormancy, in the lung. Surgical outcomes in patients with metastatic lung tumor will be improved if a method of controlling this increase in dormant metastases is established.
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Abstract
A new cell line derived from a spontaneous canine leukemia was established and designated GL-1. The cells have been cultured in a floating fashion and passaged for over two years. They were round with rich cytoplasm containing many rough endoplasmic reticula and mitochondria. Peroxidase staining was negative. The nuclei of many cells were round, but segmented nuclei were seen frequently. The doubling time of the cells was 27.3 hr and they had 78 chromosomes. Surface marker analysis using monoclonal antibodies (MABs) and flowcytometry revealed that GL-1 possessed CD45 and surface IgG. However, the cells did not react with MABs detecting T-cell markers. These results indicate that GL-1 has a lymphocytic lineage and is derived from a B-cell leukemia.
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